Yankee Hill Machine Co MLOK Grip Assembly w/Storage, Black Finish YHM-5420A This ambidextrous vertical grip is a simple" lightweight" and cost-effective device which secures tightly to any M-LOK mounting system. The low profile vertical grip design provides a positive hand hold in a small package. Adequately sized to allow the hand to take control of the front of the rifle" but not large enough to get in the way. The battery compartment will fit two CR123 batteries.