These are a nice bit of extra insurance from having your tension rods coming loose (de-tuning) when the drum is played hard. They fit onto the top head of your tension rods and press against the outside of the hoop to keep the rods from turning. White Nylon Simply thumb press over a tension rod head with a corner touching the rim. You spend all that time and effort tuning them, so why would you let that sound just slip away? Play with confidence knowing your sound will be consistent song after song, night after night. Holds your tuning. Won't vibrate loose, top or bottom. Grips all square head rods.