Unidentified Irish Regiment Collars

[Col Blacker]

Hi all,

I was hoping someone can positively identify what regiment these collars belong to? They might be UDR or RIR but I am unsure!

They are made from white chrome metal and measure from top of crown to bottom of harp 31mm and 19mm across at the widest point.

They have two fixing blades on the back.

Any help is very much appreciated.

thank-you

Sean