Suitable for mounting OEM HD grip fittings, levers and grips, preferably Rick's ''Good Guys''Clamping area 1 1/4'', 31.8 mm, conically reduced to 1'', 25.4 mm on the outside Made from high-strength 6061 T6 aluminum25% more stability than other manufacturers3,6mm wall thickness in the riser clamping areaSuitable for HD heated grips