All BKKP pad inserts are the same 3/8" thickness; the difference is in density. The Lightweight pad inserts feel comfortable immediately, but break in quickly. Free Tip from Your Bee: Once a pair of inserts is toast, don't throw them out; just layer a new pair on top of them. Test them out and find your comfort! Refresh your Bee's Knees by replacing the inserts as often as you want.