Sirui PA-20 Panning Base attaches directly onto your tripod for 360deg. panning or can be placed on top of a ball head – converting the ball head into a panoramic head. It has an Arca-compatible base that slides directly onto any Arca-compatible heads’ quick release clamps. When attaching the PA-20 directly onto a tripod or monopod the foot is removed to expose a flat stable surface. The rotating base has engraved degree marks and allows you to make quick and easy adjustments your camera when shooting panoramas. The PA-20 is rated to hold up to 11 pounds and fits both 3/8″ and 1/4″ mounting studs.