Dr. Pulley Sliding Roller Weights 25x17 (14g) Size: 25x17, Set of 8 Fits Aprilia Atlantic Sprint 400/500 ('05-'08), Aprilia Scarabeo Light 400/500 ('06-'08), Aprilia Scarabeo 500 ('07-), Piaggio Beverly 400 ('06-'07), Piaggio Beverly Tourer 400 ('08-'09), Piaggio Beverly 500 ('05-'08), Piaggio Beverly Cruiser 500 ('07-'09), Piaggio MP3 400 ('00-'08), Piaggio MP3 LT 400 (2009), Piaggio MP3 Mic 400 ('08-'09), Piaggio MP3 500, Piaggio X Evo 400 ('07-'09), Piaggio X8 400 ('06-'08), Piaggio X9 Evolution ABS 500 ('06-'07) and many more. Increases acceleration and re-acceleration properties Broadens your range of gear ratios; Increases top end speed Lasts longer than standard roller weights