These screws are for the #855 muffler and adapter OSMG2558 FEATURES: Black steel construction INCLUDES: Two 4x18mm screws w/.7 pitch threads (mounts muffler to adapter) Two 4x15mm screws w/.7 pitch threads (mounts adapter to engine) One 3.5x12mm screw w/.6 pitch threads (mounts adapter to engine) REQUIRES: A 3mm hex wrench a 2.5mm hex wrench COMMENTS:The 4x15mm & 3.5x12mm adapter screws are available separately OSMG5790 5/7/04 JCT updated tjt 042205