Here's a picture of one i had from a 2001 M900ie I think. Mounted on my 750SS along with a centre stand, which shows you how they fit.
I sold that to Richardduke, but I'm not sure if he sold it on or still has it?
An ST2/4 one is the same if you can find one with a straight leg, most have a wild kink in them!
https://www.ebay.co.uk/itm/254784872...3ABFBM-PypmoVi
https://www.ebay.co.uk/itm/314252737...Bk9SR-Tf7JqFYg
Those seem stupidly pricey, but you can hunt around now you know what you're looking for.
Also found these, which is handy, as I couldn't track them down before.
https://www.ebay.co.uk/itm/234975279246