Safariland ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster Glock 17/22/31 Right Hand STX Tactical Black. The ALS (Automatic Locking System) secures the firearm upon holstering while the SLS (Self Locking System) clicks into place for additional safety. Both mechanisms release quickly to allow a smooth efficient draw when every second counts. Specifications for Safariland 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster: Manufacturer: Safariland Gun Make: Glock Barrel Length: 4.5 in Holster Material: SafariLaminate Accessory Attachment System: Strap Holster Type: Drop Leg Holster Thigh Holster Retention Level: Level III Application: Tactical Quantity: 1 Fastener/Closure Type: ALS - Automatic Locking System SLS - Self Locking System Features of Safariland 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster ALS (Automatic Locking System) secures weapon once holstered SLS allows for a smoother single motion draw and greater protection against attempted weapon takeaways Hood Guard is standard; optional Sentry available Simple straight up draw once all releases are deactivated Suede lined to protect handgun's finish Package Contents: Safariland 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster What firearm models does the manufacturer say Safariland 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster is compatible with? The manufacturer suggests that Safariland 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster is compatible with Glock 31 Glock 17 Glock 22 Glock 22 Gen 5Safariland 6304-83-131-MS30: 6304 ALS/SLS Glock 17/22/31 Tactical Drop-Leg Holster Glock 17/22/31 Right Hand STX Tactical Black