The Canon AB-E1 is a very handy accessory bracket that can be attached
to the tripod screw on the base of the camera or battery grip; In
addition, there is an accessory shoe and also a 1/4 inch threaded screw
hole; It can be used in conjunction with other EOS accessories; The
AB-E1 is designed to mount the GP-E2 and WTF-E7 on a camera when their
primary connections are in use; It is mainly ideal for holding
additional items close to the camera.