L'antre Du Dingo checks out how the CyberGun Colt Junior 25 Auto GBB Pistol fares in this review. This is made by WE Airsoft and for its size it's still is a gas blowback rather than a fixed slide gas pistol. It has around 227fps muzzle velocity and comes with a 6-BB round magazine capacity.
The compact WE-Tech Colt Junior .25 ACP GBB Pistols are available at Evike.com and it looks like they are good sellers. According to Evike.com, it is the perfect concealable pistol for an emergency backup or simply a holdout gun for in-game scenarios. It is officially licensed with full markings and the disassembly mimics the real life counterpart.
A quick overview video of the WE Airsoft Colt Junior GBB Pistol that is available at Destockage Games... "Opt for the smallest airsoft gun on the market! The Colt Junior is a full metal gas blowback pistol (GBB) designed by WE. It is inspired by that developed for the American OSS forces, after the Second World War. This replica features official Colt markings."
Nonocat does a very quick video shooting with the Cybergun Colt Junior 25 Gas Blowback Pistol which is perhaps the cutest GBB pistol that is easily concealable. Made by WE Airsoft, this licensed Colt trademarks, a 12cm length, and a magazine capacity of 6 BBs. It's a good backup pistol as long as you remember where you put it in your webbing given how small it is.
Flubblud got a new review up and it's one of the smallest GBB pistols in the market, the CT-25 Colt Junior from WE Airsoft... "Heres is a review of the smallest fully functional GBB airsoft pistol available on the market. A replica of the famous Colt Junior, the WE CT-25 is a solidly built gun that brings concealability to the next level."