The Fatty Object CO2 Inflator with 38g Catridge is specifically designed to inflate fat and plus-sized tires. The inflator is made of precision machined aluminum, and is compatible with both Presta and Schrader valves. Considering it's made for fat bikes, Portland Design Works incorporates an oversize control knob on the inflator that lets you control the flow with gloves on, a nice feature for trailside repairs in frigid temperatures. The package includes one threaded 38g CO2 cartridge capable of filling a 26 x 4. 8in tire to 6 - 7 psi or a 29 x 3. 0in tire to 20 - 22 psi, as well as a lightweight foam insulator sleeve that helps prevent the cartridge from freezing your hands as it cools down during inflation.