Easy to use, easy to control and affordable. The Genuine Innovations Mircoflate Nano gives you the best bang for your buck when it comes to quality and ease of use. Simply thread on your favorite CO2 cartridge, twist the cartridge off slightly to engage inflation and tighten it back on to shut it off. One 20g cartridge would be enough to inflate one 27.5x2.5 tire to 30psi or one 29x2.4 tire to 40psi.