A device is convertible between a knife and a fore grip of a firearm. The device has a grip body operatively connected to a blade, and an attachment member connecting the grip body to a longitudinally extending rail of a firearm. The blade converts between an extended position when the device is disconnected from the firearm to a stored position when the device is connected the rail. The blade remains oriented along the longitudinal axis of the grip body when it is in both the stored position and the extended position. The grip body remains operatively connected to the blade when the device is disconnected from the firearm and the blade is in the extended position.