Fast'Air combines a CO2 cartridge with tyre sealant, inflating your tube and sealing punctures up to 1mm across in the process. It sounds like an ideal – if expensive, per puncture – quick fix. And if you’re running tubulars or tubeless tyres on your mountain bike and you don’t have a spare, it certainly is ideal.
The sealant works well but we found we still needed a hand pump to get a road bike tyre up to sufficient pressure. Also, you can get messy blowback from the foamy sealant unless you leave the Presta/Schrader hose connected for a minute or so after use.