The PTS US PALM AK Battle Grip (GBB) is an ambidextrous, full-sized, polymer rifle grip – ergonomically designed to drive the gripping hand up into the receiver/grip junction for enhanced control. The side also includes texturing for a positive grip. The GBB US PALM Battle Grip variant features a storage compartment that accepts CR123 batteries, tools, spare parts etc.:

PTS US Palm AK Battle Grip for GHK / KWA GBB (Dark Earth)
Reinforced Polymer Construction
Includes storage compartment measuring 80 x 45 x 19 mm
Ambidextrous design.
Suitable for GHK/ KWA GBB Rifle

Dimension – 104 x 86 x 26 mm (approx.)