A very competent little stick, Nothing special in any way, just functional and comfortable. And cheap!
It's very similar to most sticks internally - a giant PCB with the encoder on it also connects all the buttons, there's a stick and a couple of tiny PCBs for the start and select/Z buttons. Nothing to it.
The mechanism is not recognized - might be a Hori custom job?
There's nothing remarkable about this stick at all. There are three versions, two for GC and one for Playstation.
The GC version of this stick (without the Soul Calibur artwork) has a boring purple faceplate with a vertical fade. Part number HGC-31.