So was the WW1 & WW2 brown leather jerkin a military sleeveless jacket with a thick lining the same material as the old battle dress . Mine was OK for working outside in minus 18 oC which one year in Northern Germany on cold weather exercises & aiding the civil powers was quite often.
Just seen the above post ..
Yes that's them , magic gear ,rain resistant too. certainly better than the instant melt non heat retaining quilted nylon waist coats we got give to go with DPM camo combat gear in the mid 1970's .
