6600 series 7/16" crown 16 gauge
fits Spotnails 6600 series staplers, Senco "N" series staplers including M1, M2, M2+, SNS45, SNS40, SNS50, and Hitachi N5008AB, N5008AC & others
6800 series 3/8" crown 18 gauge
fits Spotnails 6800 series staplers, Senco "M" series staplers, Duo-Fast W-18 series, & others