Sunwayfoto's Custom Plate for Canon 1DX is compatible with "Arca-Standard" 39mm dovetail camera plate heads and camera plate adapters. This custom plate is made specifically for the 1DX and features a radian design to prevent the 1DX from shifting. The plate has two 1/4" threads -- one for the camera and one for a monopod -- and two M4 threads that enable the plate to function as an L-bracket for use with vertical plates.