The CRL Newborn Ratchet Rod Gun is a professional model drop-in cartridge gun with a 2" x 8-1/2" (51 x 216 mm) barrel that holds all standard size caulking cartridges. The ratchet action rod pushes caulking material smoothly with double, heat-treated dog drives for even application. It's one of our most popular guns because it has a good combination of the following features at a very affordable price: seal piercing tool, nozzle spout cutter, ladder hook, adjustable wrist strap, and no pinch finger guard.