Every now and then something comes along and renews my passion for staplers. Best described as a "Franken-stapler", the M-100 is a S-100 with a modified jaw. I have every reason to believe it was Neva Clog factory modification as evidenced in the photo below from a recent online auction. The box is labeled "Special Neva Clog Stapling Plier Model MB-100," indicating the MB-100 is most likely a modified B-100. It gives me great hope to know there are more Neva Clog "Special" staplers out there. From browsing Neva Clog patents, I know there were many more stapler designs than staplers I've seen and that means many more Neva Clog to find. Cherchez l'agrafeuse!