Who makes this rear sight on my #1

[contender85]

I picked up a nice #1 in 45-70 awhile back and it has this rear sight on it, any idea who makes it?

Thanks,
Mark

 

[beentheredone]

XS -- I think...

 

[UmpquaCharlie]

Agree XS

 

[KurtC]

XS started out as Ashley, hence the A.

 

[contender85]

Thanks for the information.