Cube Connector for TR01 Mini Tripod with Friction Arm and Arca-Style Clamp. Can be used on tripods, and camera accessories;
A25 has four 1/4"-20 and two 3/8"-16 threads.
The thread size is the same on top and bottom. Would be better that 3/8 on one side and 1/4 on the other that way you could put it on a larger tripod and use magic arm for ex doing macro.