Pistol retention levels; I II III...
If by "retention" you mean a simple thumb break or security strap, there are a few decent brands to shop with; Safariland, G&G, Galco, DeSantis, Kramer, Blackhawk, Blade-tech, Fobus, Bianchi, High Noon Holsters, Don Hume etc.
Security levels, II, III and even IV mean more retention devices.
A UM92 could fit a CZ75 pistol & do okay for range or field-outdoor use but I wouldn't suggest it for concealment or regular uniform duty-patrol use.
Clyde