Unich CO2 Injector Pro Pump

The Unich CO2 Injector Pro is a flexible and well-engineered design, with a price tag to meet or beat premium brands such as Lezyne or Birzman.

It isn't the lightest inflator out there, weighing in at 52g excluding the 16g cartridge (the lightest inflator in Mr Smithers' private collection is a scant 17g in comparison, but that's a push-on variety that only takes threaded CO2 cartridges). The standout design features of the Pro are that it's a screw-on fitting for both Presta and Schrader valves, it has a press-button flow control, and, critically, it takes both threaded and non-threaded CO2 cartridges.

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Depending on where you buy cartridges from, there can be a real premium – approaching double the price – for threaded cartridges. Unthreaded cartridges also tend to be more widely available, at sporting retailers and big-box stores like Wal-Mart catering for paintball, airguns and other uses, so you're less likely to be left 'ungassed' following a discharge far from a cycling-specific retailer.

The cartridge – threaded or non – is stored reversed in the body of the Pro. It does rattle ever so slightly inside, so benefits from a sliver of inner tube to keep it silent. When needed, you unscrew the body, turn the cartridge around and do the body back up. No gas escapes during this process. Note that once the canister is punctured you can't remove the body again without letting all the gas escape, as the cartridge nozzle receptacle itself isn't threaded.

Assuming all tube repair or changing protocols have been followed, screw the inflator onto the valve, Presta or Schrader (the knurled head fits securely onto both types), then the button on the back facilitates gas release. This is controllable, the pressure required on the button being quite firm – no chance of accidentally discharging here. As expected, a 16g cartridge filled a 28mm 700C tyre to around 85psi. During filling the Pro did get cold to the point of condensation, but not uncomfortably so for a naked hand.

After inflation the head is easily unscrewed, but being metal it's the coldest point, so take care. The press button can then be used to release the remaining 85psi of gas before the cartridge is removed.

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Doing a leak test over a couple of hours in water after threading the cartridge on showed no bubbles. If you're only using the Pro to top up a partly inflated tyre, you could keep an eye on any possible leakage by weighing it over a period of weeks to see how much CO2 is remaining, having first weighed it unused, of course.

As the cartridge needs to fit inside the body, you are restricted to 16g cartridges, so this is not for high-volume high-pressure uses. But if you're looking for a one-piece solution to use with threaded or unthreaded 16g cartridges, for Presta or Schrader valves, the Unich CO2 Injector Pro is a good-looking option. Pricey though.

Verdict

An elegant CO2 inflator with flexibility designed in – but pricey