Vertical foregrips have been around a long time, going as far back as the Thompson submachine gun nearly 100 years ago. Having a firm grip farther out on a longarm assists in controlling rapid-fire applications, and helps stabilize off-hand shooting by helping lock the carbine into the shoulder.
Recently, angled grips have gained popularity along with the "C-clamp" hold far out on the barrel. It allows precise control of the rifle during multiple target engagements, such as in the rapid pace of a 3-gun match.
FAB Defense offers the PTK VTS Combo, which pairs an ergonomic angled grip with a "Versatile Tactical Support" (VTS) that provides a stop for the support hand while using the grip. The support hand is positioned wherever desired on the fore-end, and the grip even contains a storage compartment for spare parts or extra batteries.
MSRP: $57.75. Available in OD Green and Flat Dark Earth as well as black.