Arrow T50 1/4" type, Senco H, A11 series fine wire staples by Fasco. Interchangeable with Duo-Fast A-11, Arrow T-55, Senco A-11, Rapid 11, JK671, Senco A-11, Rapid 11, JK67, Prebena PF.
Fits Fasco F1B A11-16, AUTO, L/M air staple guns, Arrow CT50K, ETFX50, ETF50BN, ETN50, HT50, T50PRN, ET50, ETC50 electric staple guns.