Summary Designed to fit the standard 1/2" x 14 BSP thread found on all paintball CO2 tanks. I use paintball CO2 tanks with an adapter for my SoadStream Machine. I was tired of having to keep the empties in one place and the full tanks in another. With these, a quick glance will show their status. You could print them in any color and with any text on the label for other uses. OK for full, MT (an old welding term) for empty. The threads are correct (not just for show). It takes me a couple of on's and off's to get the threads clean. But after a few uses they will screw on and off with relative ease. Print Settings Printer: Wanhao Duplicator 6 Rafts: No Supports: No Resolution: .15mm Infill: 20%