This has been available in the US for a while but under a different brand name (Kissmart). And it stinks. It doesn't stay on the charger well and it is useless for on the go. Much better off getting a tiny battery bank if you have to charge without an outlet.
A portable charger for your keychain is designed to simplify the use of Garmin smartwatches while traveling, as the watches can be fully charged via the charger's integrated battery. The 44-gram power bank is compatible with more than 60 different Garmin smartwatches.