This is a nice REPRODUCTION Sleeve Diamond in Bevo for the HJ/BDM Uniform. Insignia measures 56mm tall x 33mm wide when folded (last photo shows an example folded and sewn to a blue wool backing).
I see this identical patch offered for sale as original on the Internet for $60; however, it is known to be an older repro from the early eighties. I have two dozen of these so hit me up if for some reason you need a quantity discount.