Hi Henry, I would contact BRG-USA Customer Service directly to inquire at - https://brg-usa.com/contactus

Henry, not finding any available. I would contact BRG-USA and ask what footprint it has, and go from there. https://brg-usa.com/contactus

Henry, unfortunately I'm not finding any type of adapters for the BRG-USA BRG9 Elite 9mm 4. Also depends if you have the optics ready version or not. If you have a standard version that isn't cut to accept red dots I'd contact the manufacturer and see what size dovetail the rear sight uses to see if it's compatible with any other firearms. If so you can likely purchase a dovetail adapter that replaces your rear sight to add a red dot that way. If you have the optics ready version just ask if they sell adapters for the Sig Romeo because I'm not finding them anywhere else. You can contact the manufacturer by emailing ( info@BRG-USA.com ) or here's a link you can use to message them. Sorry but hope this helps, link here.................... https://brg-usa.com/contactus

As mentioned below, I'd contact BRG-USA customer service to get a better answer.