United Kingdom
 
British “15th/19th King’s Royal Hussars” dress visor cap
Not quite correct, since the hat should be red with a black peak. Oddly, the badge matches the side buttons — which are difficult to replace as they are sewn on. Go figure. Picked this up in a junk shop in Birmingham, England in 1998. Many thanks to ex 5&9er Bob Garvan for tipping me off about the correct color combo!