The OConnor O-Box WM Studio Adaptor (15 mm) is designed to work with O-Box WM Matte Box. It has 2 protruding studs, which fit into the LWS holes on the O-Grip bridge and can then be attached to 19 mm studio rods.
OConnor C1243-1119 Features
Designed to work with O-Box WM Matte Box
Studio adaptor takes the place of the LWS bridge
Features 2 protruding studs which fit into the LWS holes on the O-Grip bridge, which then goes onto studio rods