we can supply all kinds of nylon insert. nylon insert Railway bolt: T bolt, Hs Clip Bolt, Track bolt, ... 687, ZW700Insulator: Pandrol series #7,#8, #9, #11,#12, #13 Nylon insulatorsLock washers: wL20, WL24, Wl22Flat washer: Uls6, Uls7Nut: Nlyon nut ...