bipods

A bipod is a V-shaped portable attachment that helps support and steady a device, usually a weapon such as a long gun or a mortar. The term comes from the Latin prefix bi- and Greek root pod, meaning "two" and "foot" respectively.Bipods are designed to support the weight of the weapon's front portion and barrel, and provide significant stability against unwanted side-to-side movements (i.e. canting) while allowing free movements pivoting around the transverse axis (pitching). Most modern bipods have foldable and/or telescoping legs, and allow some limited movements around the vertical axis (panning) and even the longitudinal axis (tilting).
A bipod by itself, with only two supporting legs, is not completely stable and needs to be reinforced by at least one more point of support to be steady, especially against the horizontal shearing force from recoils. This third point of support is typically the buttstock that is firmly pushed/braced against the shooter's body, but can also be a baseplate (in mortars), sometimes with additional support from a monopod or a bean bag.

View More On Wikipedia.org