Our Premium Heavy Duty Staples were developed for optimum performance in most heavy duty staplers. Constructed from superior quality high carbon wire to reduce buckling and jamming. The finely honed chisel points deliver maximum penetration for maximum sheet capacity. Optimized 3/8" (9mm) leg length to drive through a substantial 25-55 sheets. Each box includes 1000 staples. Sold as 3 boxes for a total of 3000 staples. For optimum performance in most heavy duty staplers. Finely honed chisel points for maximum penetration. Superior quality high carbon steel wire reduces buckling and jamming. 3/8" (9mm) leg length staples 25-55 sheets. 1000 per box, sold as 3 boxes, 3000 staples total. For use in heavy duty staplers: 00540, B310HDS, 03201 and other branded heavy duty staples. Age: 6+ years/Grade K+