Genuine Echo Bolt, Hex 5 X 55 Part #: 90010505055 Fits models: SRM-1501, SRM-2010, SRM-210, SRM-2100, SRM-2100SB, SRM-210i, SRM-210SB, SRM-210U, SRM-211, SRM-211i, SRM-211SB, SRM-211U, SRM-22GES, SRM-22GESU, SRM-230, SRM-2301, SRM-2305, SRM-230S, SRM-230U, SRM-231, SRM-2310, SRM-231S, SRM-231U, SRM-251, SRM-260, SRM-260S, SRM-260SB, SRM-260U, SRM-261, SRM-261S, SRM-261SB, SRM-261T, SRM-261U, SRM-270, SRM-270U, SRM-3000, SRM-3001, SRM-3010, SRM-400, SRM-400U, SRM-410U