Taller Cap = Longer Stroke = More POWER. Generally, the standard Omer cap is sufficient for normal demands, but sometimes a batch of Medium Density Fiberboard or a run of extra densely grained wood, screams for MORE power! These tools with an "A" suffix to their model code, indicate that extra "oomph" that can make all the difference in some applications. 18 gauge Narrow Crown (1/4") 90.38 A is used throughout cabinetry, furniture and on site con...struction applications where a medium size tool is prized for power to weight ratio and the attention of Balance that Omer is known for. Narrow Crown (1/4") 90.38 A staplers answer those window door, cabinetry and case goods sweet spot p operators need with a product that is hard to find. Small enough to get into some tight spots...but with power enough to drive into dense and demanding materials that appear out of nowhere. 5/16" medium crown 92.38 A is a nice in between staple type that has been the "toast of Europe" for decades and is being seen on this side of the POND a lot these days in North American wood working. Omer staplers are designed and manufactured entirely in Italy and thereby infused with quality and attention to detail second to none. In addition to their normal Bump Fire, do review our firing mode section to see Sequential and Remote Fire Trigger options.