Tactical Scorpion Gear For Glock 21 Modular Level II Retention Paddle Holster Option 3: Holster with Paddle Platform, Belt Loop Adapter and Drop Leg Platform Quick Release Button: Level II Quick-draw holster with safety locking mechanism. Compatibility: Glock 21 Superior Material : Made of durable lawenforcement grade polymer materials The combat-proven Holster is a step forward in holster design and technology.