The XTrade Skeleton Caulking Sealant Gun, designed for 310 and 350ml cartridges The XTrade Skeleton Caulking Sealant Gun is for Mastic Silicone Caulking Cartridges 310-350ml. The XTrade Caulking Gun is the obvious choice, with a skeleton gun format and metal frame. Because it has an extended frame you'll get compatibility with 310ml and 350ml cartridges. This assures a reliable and smooth application. Features: Will accept up to 350ml tubes Advanced professional applicator regular, repeated use Designed for 310 and 350ml cartridges of acrylics, silicones, MS polymers and adhesives Specifications: Compatible with: 310ml and 350ml