The M.P.s (Military Police) garrison side cap is made in the brown (O.D.) wool colour and is fitted with the braid piping for the Military Police. The O.D. (Olive Drab) wool garrison cap was worn with the A class dress uniform (4 pocket tunic or the short Ike jacket) and when you wearing the M9137 wool trousers and wool shirt, or with the likes of the M41 field jacket.
eBay