These are great - I just installed them in my 3rd generation Toyota Tacoma and they're bright as heck. The press-fit into the Tacoma's stock rear light housing is really tight - I'm not worried about water intrusion one bit. I did use one of the supplied red o-rings, but I didn't spend much time deliberating between zero, one, or two o-rings per piece. I just don't think it will be a problem.The blade connector fits where a normal bulb would, and for that reason, I got some 1.5" shrink wrap with adhesive inside and a good heat gun. I installed the shrink wrap around the original housing and blade connector. Hopefully I won't have to cut it off for many years.I'm impressed with the quality of the aluminum heat sink - It actually looks better than a lot of the photos on here. Looking at the way it is constructed, I do believe that it is functional and will help the LEDs last longer. Seems like a great product!