This is the replacement Clutch Nut for the Tower Hobbies Tower Terror This nut threads onto the engine crankshaft and secures the flywheel. FEATURES: Steel construction, Black in color Replaces a worn or damaged clutch nut INCLUDES: One Clutch Nut - key number 96 REQUIRES: Installation SPECS: Length: .35" (9mm) Hex Size: .39" (10mm) Thread Size: ¼-28 COMMENTS: For the flywheel order TOWC7531 kpm01/23/2007 ir/jxs