Neva Clog produced many models of plier staplers to perform different tasks. As the J-30, J-60, and J-56R were more suited to the office, the S-100, F-100, and B-100 models were meant for tougher tasks. I've found reference to them used by leather workers and even corn breeders (Maize Newsletter Issue 15, 1941). As seen illustrated below, the S, F and B-100s varied in jaw opening size. The S-100 and F-100 used either A-1000 (1/4" leg) or L-1000 (5/16" leg), where as the B-100 had it's own B-staples. If you find yourself confused by all the stapler and staple model numbers, you're not alone. There's really no discernible logic to these names but it's interesting to hypothesize what different things one would staple with each model. I measured and my index finger would fit in a 1/2" jaw opening which brings back a rather unhappy childhood memory. You can fill in the details. Luckily, these S-100s only have 9/32" of clearance so I won't have to relive that experience.
Excerpt from the Stapler of the Week, October 18, 2007.