TECH NOTES These are the Muffler Extension Screws for the #873 Muffler Extension OSMG2578 FEATURES: Black steel construction INCLUDES: Two 3x50mm black steel cap head screws w/.5 pitch threads REQUIRES: A 2.5mm hex wrench to install KrH 10-14-93 complete update tjt 042805 BOX DIMENSIONS: 2.13″ W. X .25″ H. X 3.50″ L.