This kind of corrugated fasteners is called SENCO type corrugated fasteners X06,with a crown 24.8mm and 3/8" in length.it fits tools such as SENCO SC-2, BeA W15-358, Duo-Fast CF series,Haubold WM series,OMER CF series,Atro Panta WC/CF.
SENCO type corrugated fasteners X06 (3/8")