First, this is a good product if you want to tint your tail lights on a budget.  However, there are many drawbacks to using this product.Pros:Affordable alternative to otherwise time consuming tinting or opting to take it to a costly shop to have it done "right".When done "correctly" you may achieve good results.  However, doing this job correctly may take some knowledge with painting/color sanding and other prep work related to body work.Cons: Easy to mess up, by messing up I mean getting runs from spraying too wet/close, nobody likes the runs.Does not hide imperfections.Easy to apply too much when you think you still might want them a little darker.There really are no instructions on the can.  Do not expect the can to tell you what to do/what not to do.  From MY experience with this or any product I can however give some general rule of thumb tips.  Some will still have their drawbacks.This is how I did it:You will need:  Dawn dish soap.  Original formula!  Not the newer "ultra concentrated". Spray bottles at least 1, 2 are better.  Latex or equivalent gloves.  2000 Grit wet sanding paper.  Running alcohol 50/50 water mix.  Water (obviously), masking tape, a solid flat surface to work on, quality lighting, quality ventilation, and the VHT/Clearcoat, of course. Finally, A LOT OF PATIENCE. Optional:  Meguiars ultimate compound, microfiber towels, a dual action polisher/soft buff polishing pad.Step 1.  I REMOVED my tail lights.  No sense trying to spray them on the vehicle, unless you want to spend all of the time to mask it off correctly at which point you would have them off by now anyway.Step 2. PUT LATEX or VINYL GLOVES ON!!! You'd be amazed at how much oil your hands are producing and believe me, it will effect your overall quality of work.  I followed up my soapy water wash with a 50/50 alcohol/water mix for final prep prior to sanding.  I thoroughly cleaned the tail lights with good old fashioned Regular dawn dish soap and warm water, followed by a rinse off.  Sounds cheap?  You'd be surprised how far back the ORIGINAL formula dawn dish soap has been utilized in the body industry, it is a great degreaser.Step 3.  Put a new pair of gloves on. Don't want to get waterlogged or have water running out of them.Step 4. Mask anything on the light that you don't want sprayed, IE: Inner edges, reverse light, whatever. I wet-sanded my tail lights with 2000 grit sand paper and another solution of dawn/water via spray bottle.  Keep the paper/surface wet.  Make sure you sand the entire surface uniformly and with mild pressure.  Don't try digging yourself through the other end of these lights, we will get to the reason why I myself chose the 2000 grit and nothing more abrasive or nothing at all a little later on.Step 5.  Rinse off your headlights, lightly towel dry them and inspect.  Let them dry completely.  They will appear hazed/foggy.  Any spots that you missed or didn't scuff up enough will retain it's original gloss and should be corrected prior to advancing to the next step.Step 6.  Once you are satisfied with your wet sanding I recommend following up with another misting via spray bottle of 50/50 water/rubbing alcohol to be certain that the tail lights are free of any dust/grease particles prior to painting.  It never hurts to be safe and by the time you are done doing all of this work you will either thank yourself in the end or curse yourself for not taking that one last just in case effort.Step 7.  Apply light, uniform coats of the VHT night shades spray tint.  I applied my first coat at a distance around 8-12".  Maintain some level of overlap to assure uniform coverage I recommend anything from 25% overlap min to 50% overlap max.  Spray the edges first, work quickly yet taking your time, if that makes sense. Depending on humidity and temperature I would let the first coat sit for bare minimum of 10 minutes before applying any additional coats, if its cool or humid wait about 15 minutes, don't fall into the urge of touching the surface to check whether or not it feels dry to touch, especially if you ever plan to use your tail light for committing a crime.  Your prints will be etched into them and forensics will be all over it.Step 8.  Let it dry, dry, dry, I recommend waiting a bare minimum of 45 minutes to an hour before clear coating.  You do not want to let the clear coat blend into the paint.  This might be overkill but if you clear too soon your lights will look dull/cloudy.Step 9.  Apply clear coat, some people recommend as much as 4 coats, 6 light coats, whatever you desire basically.  Clear coat is a little bit different, you should spray it on wet enough to assure you don't have "dry" little specks all over yet it is very easy to get it to run.  You have already gotten this far without messing up so just like painting take your time.  Spray the first coat on light, follow up with one, maybe even 2 wetter coats. I think anything more than 3 general coats is overkill.Step 10.  Let it dry, dry, dry, no, it's not ready to be touched yet!  Let it dry for as long as possible before handling.  I would recommend letting it dry no less than a few hours before handling, just to be safe.  If possible, let it dry for at least 6 hours before re-installing them on your vehicle.  If it is going to rain later on that day/night I would recommend just installing them the next day.OPTIONAL..  There are 3 possibilities here.  You are either finished at this point, if so, congratulations on a job well done!  OR, you can continue on to the steps, OR, you have made a mistake and are not satisfied.  If you have made a mistake swallow your pride and let these things dry for as long as possible before attempting to follow all of the steps over again if going the sanding route.  Acetone, goo gone, or whatever you might consider using works great when the product is still in its out gassing/curing stage if you would go the quick fix method where time is money.Step 11. You may have noticed orange peel, (little bumps all over the place)  Don't worry, you didn't do anything wrong this is entirely normal with clear coat.  This can be corrected very easily by letting the lights dry for no less than 24 hours IMO and gently once again wet sanding the clear coat smooth with 2000 grit wet sandpaper. Same soapy water mix, light pressure, work a little at a time and a squeegy works great for wiping off residue to show you how much work you have left to do.Step 12:  So you are all smooth, and now your work surface looks like crap.  Darn, he got me, all this work and now it's all hazy/messed up.  Did I just scare you?  You can remove this haze by using Meguiars ultimate polishing compound(which I used) or equivalent.  I have a lot of experience with a dual action buffer I used gentle pressure on a low speed and lightly agitated the surface with my soft buff foam polishing pad. Work it long enough and you can probably achieve comparable results by hand.  I followed up with a finishing glaze/gentle hand buff for optimal results.Step 13:  Now those are some nicely smoked tail lights, congrats!So I gave a lot of steps, everyone has their own feedback based on their own experience, or lack thereof, are all of these steps necessary to everyone?  No.  But, they were how I was taught and my overall desire to make the most out of my $20.00 spent.  I just recently did a full repaint on my 1994 Ford Bronco Eddie Bauer that used to be a rust bucket, no, I didn't use spray can I used PPG omni urethane automotive dual stage paint w/my spray gun and achieved great results.  I wouldn't have achieved those results without proper preparation/precautionary measures, painting is actually the easy part of body work.  So I didn't want to throw a hurried up/half asked job of tail light tinting on my otherwise nice looking vehicle.  I am an automotive detailer and have my share of experience in the field of auto body work as well so I am very picky about how something looks, especially when I do the job myself.Either way you get what you pay for and this is a "spray can" job.  Following my own knowledge I made the most out of what it is and they turned out rather nice.  I wouldn't recommend more than 2 coats as 3 is too much IMO (I've learned from my own mistakes) and like the other reviewer said your lights can be very hard to see through especially in the day time because of it.  1 coat offers little results (too light, just barely darker than stock) and 3 too dark, 2 seems just right IMO.  Unless you like that really black look and aren't too concerned about safety for yourself and others, or if you are doing really light coats.Make use out of the flash times between coats and do yourself a favor and walk away.  It is far too easy to get a sense of urgency and over excited and want these things back on your car/truck.  It's MUCH better to wait 5 minutes too long than 5 minutes too soon.  And for heavens sake, DON'T TOUCH!  At least not yet.  Try to do this on a day when the air temperature is at least 65 degrees with low relative humidity.  Dry warm air works much better to help you than cool/moist air.  Try doing this in a dust free/bug free environment.  I have too much experience painting in my own garage and for whatever crazy reason bugs seem to LOVE the scent of paint materials...  I actually bought a garage door screen to help prevent them from coming in yet still provide adequate ventilation.  That's just me though, I didn't buy it for this purpose I bought it for purposes like this on a frequent basis.Safety first! (yet I managed to think of it last) If you are really worried about health wear a particulate respirator and safety glasses.I know this is a long review and I know everyone has their own opinion on what should/shouldn't be done.  The reason I listed the tips is for the new to this type of work person that has an interest in undergoing this project on their own with little knowledge on how to do it.  If you have old/beat up lights to work with consider replacing them before undergoing this project. OR:  Wet-sand with a 1500 or even 1000 grit paper and follow up with a 1500-2000 grit.. Personally I know from experience that the 20 year old tail lights on my vehicle that were scratched and scuffed didn't turn out well... I replaced them and now I am much more satisfied with the end result.One final note, - THE REASON IT ONLY GETS 3 STARS - I promise it's the last thing I'll say... For the skeptics/what to REALLY expect.  If you wet sand with the 2000 grit paper you will likely see minor imperfections under the paint/clearcoat  This is why I didn't do anything more abrasive than 2000 grit... This will show more prominently under direct light instances and up close inspections..  This is because this tint/clear coat really doesn't have any filling properties like you would expect out of a primer.  With that being said, obviously you can't prime your work prior to painting in this case so you either have to accept a some imperfections OR you could go the route of NOT wet sanding and go straight to painting after a good cleaning but I wouldn't do this... The reason why I wouldn't is from my own experience when you don't do some light scuffing the paint tends not to have good adhesion at all.  Making it much easier to create runs and or peeling in the more immediate future than the next guy.