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 1/2" (12mm) leg length drives through significant 55-85 sheet stacks. For use in Bostitch Heavy Duty Staplers: 00540, B310HDS, and other branded heavy duty staplers. Each box includes 1000 staples.