DROP OUT 399, CANNONDALE - CNC machined 6061 aluminum. - Black anodized finish. - Attaches to frame with (1) M3x10 Socket Head Screw. - Fastener Included. - For 12x1.0 Thru Axle (Double Lead). - Replaces Cannondale Part #K33009. ~ Note: DROPOUT-399 is for M12x1 double lead threaded axles (Cannondale Speed Release). For regular M12x1 thru axles, use DROPOUT-303. - 1 drop out per bag.