The Bobro Engineering Forward Grip Assembly is designed to be used as a monopod and as a barricade stop.
It uses a new attachment method that utilizes opposing forces in a diagonal plane to secure the unit. Additionally, the left and right sides of the grip are designed to allow the unit to be firmly secured in a clamping head on a tripod.
To mount:
Rotate the drive wheel until the driver plate is allowed to retract under spring pressure. Push the grip assembly onto the rail when the rail is between the two outer locking walls (at approximately 45 degrees) then rotate the unit until a tactile engagement is felt. Then, simply rotate the lock wheel until it stops. It is now totally secure. Due to an internal compression bearing design, it remains secure throughout firing and use.
www.bobroengineering.com/Forward-Grip-Assembly