I have been weight training for 17 years, and half of that i did not use a mouth guard. Not only can you lift heavier but you can avoid so much pain. I have cracked 3 molars in the past and headaches from heavier deads. This solves all of those issues. I will never lift without this mouthpiece and I don't believe I could of ever got to the level I am at without them. Great product, easy to personalize and your set.