1.Bottom Plate for Sigma fp Camera
2.4 x 1/4"-20 Accessory Threads
3.Built-in Flat-Head Screw Driver
4.Compatible with Sigma LVF-11 LCD Viewfinder
5.Compatible with Lens Adapter Support BSA2650
6.Locks Camera with 1/4"-20 and Locating Pin to Prevent Twisting