A Keps nut, (also called a K-nut or washer nut), is a nut with an attached, free-spinning washer. It is used to make assembly more convenient. Common washer types are star-type lock washers, conical, and flat washers.Compatible with: XLi EDGE, 90 XLi, 8290 - 90 XL, 8800, 8270, 8230, TMS, MAG3, Quest, Options, PROfile, C90, EZ Touch, Summit, Summit S, Magnum, Hot Duster