These little gizmos are excellent if you want to pump up your tyres FAST. They're incredibly simple, all of them act as a valve. Screw a CO2 canister on one end, screw the other onto your valve ...

At $109 /£89, the AS2 Pro is rather expensive—not just compared to hand pumps and CO2 inflators but also when measured against the average price of other electric bike pumps on the market.