The GL-Shock from the Mako Group (made by FAB Defense) is a recoil absorbing collapsible stock for AR-15 type rifles or shotguns that use AR-15 collapsible stocks. It has an internal spring that compresses under recoil to absorb some of the shock and soften the felt recoil. It fits onto any mil-spec or commercial AR-15/M4 buffer tube and adjusts for length just like other AR-15 collapsible stocks except that you press on the front of the locking lever instead of the rear of it. It includes tensioning tabs that minimize movement once locked in position and has QD sling mounting points on each side. Additionally, it has a water tight storage compartment under the removeable recoil pad. There is also the option to get it with or without a removeable cheek riser if you need extra elevation for good cheek weld when using optics. This is especially useful when used on shotguns with optics. The shock absorbing spring is designed for heavier recoiling AR cartridges and shotguns. The spring is a bit heavy to compress much under the recoil level of a .223 or even a 7.62×39. But anything more powerful than that and you will realize a recoil benefit from it. Since spring-only recoil stocks have their limitations as to how much recoil they can fully absorb, on a heavy recoiling 12 ga shotgun a great idea is to combine the GL-Shock to the excellent Enidine Shot Shock (a hydraulic shock absorbing stock tube which is part of the Mesa Tactical LEO recoil stock kit and is also sold seperately). Putting the GL-Shock on the Shot Shock does reduce 12 ga recoil even further on this very effective system. When using this combination, both recoil systems compress simultaneously for a very smooth recoil cycle. The GL-Shock will also be very popular for those with AR-10 type 7.62mm rifles as a way to soften things up a bit. For those rifles a great recoil reducing combination is a GL-Shock stock with an Enidine Hydraulic buffer inside the buffer tube.