This is a great stopgap for riders who need a quick smallhole puncture fix or sealant top-up in their inner tubes.
You just unscrew the valve top, or screw on the Schrader adaptor, and then press the canister onto the inner tube valve. The latex foam seals small holes and compressed air from the canister inflates the lot, all in one hit.
It's a great option for racers with a thorn puncture or a slow valve leak and we used it successfully on a tubeless tyre that developed a slow leak after hitting a rock.
The system is simple and effective but take care when attaching it to the valve because we wasted most of our first canister.
For £5.99 you can get a single canister, or you can get this kit with a frame/ seatpost clip and two canisters for £13.95. For £8.95 you can also buy a big-volume kit for tubeless tyres.