GPI Lockerz are a simple part that can be "snapped on" your tension rods in seconds to prevent them from loosening. Lockerz‚Ñ¢ can be easily removed for head changes, or leave them in place. Lockerz work with most standard tension rods and standard die cast or stamped counter hoops, so there is no need to replace any hardware. (Sorry, but at this time Lockerz‚Ñ¢ are not designed to be used with wood hoops). These are just a 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 to keep the rods from turning. White Nylon