Peak Design PROdrive Screw INDEXING AND FLAT-FOLDING When not on use, the PROdrive fold flat against your camera case. When usig, plull the D-ring out and it will stay in the open position. RUBBER NON-TWIST PAD The round non-twist pad and hex-drive (4mm wrench included) allows you to torque the PROdrive screw securely against your camera body in a way that resists backing out over time. EXTRA-WIDE LOAD BEARING AXLE Hang any camera/lens/accessoy combination securely fromn the PROdrive screw.