The SpiderPro Base, Plate and Pin from SpiderPro Camera Holster are all components of the SpiderPro Single Camera System. The Plate secures to the bottom of your camera. The Pin attaches to the Plate or the base of your camera or lens tripod mount. Both pieces attach to the Base which is the hub of the entire system. It permits you to wear your camera on the optional SpiderPro belt, or on your own. For those planning on using a SpiderPro belt – you will need a sold separately, SpiderPro ThinkTank Pro-Speed Belt Adapter.