Here we have the HXTCII Hexrack clamp designed for use with the Hexrack II. This clamp also works with the original Hexrack.
This clamp attaches a tom clamp (CL945B, etc.) or cymbal holder (CH755, etc.) to the hex-shaped pipe and is compatible with 22.2mm diameter pipes.
Its vertical angle is freely adjustable thanks to the clever inner sleeve design.