Genuine original Canon part, brand new, never used.

Canon part # YG2-3536

It's for Mark II version EF 100-400mm IS L USM lens ( MK 2).

If your tripod ring is stuck due to impact or bent, in many case, the fixed barrel also bent and need to be replaced together.

The listing for fixed barrel is here:

https://www.ebay.com/itm/183374112601

 *** Custom Declaration: If you have the concern, please message before or right after the purchase.