Bipod (5e Equipment)
From D&D Wiki
A Bipod is a clever mechanism designed to help stabilize a ranged weapon by bracing against the ground, a low wall, or some other such object.
When equipped to a ranged weapon with a logical attachment point (e.g. Crossbows, Rifles, but not Bows), the weapon's attacks no longer suffer disadvantage when fired from a prone position.
Cost: 5 GP
Weight: 1/4 lb.