Neoprene Bound Washer (07.2118.0000) commonly found on some Necky and Old Town kayaks, such as the Heron XT or the Rip. Often used for mounting thigh braces and other features. 1/4 inch ID, 5/8 inch OD. Regular washers, neoprene washers and more neoprene backed washers can be found in our multi page hardware catagory. 1/4-20-HDW