Cotton Field Cap
The olive drab cotton field cap is a visor style with retractable earlaps lined with wool flannel, and grommets for ventilation. It was designed to be worn with the M-1943 field jacket. It could also be worn under the hood of that jacket and with the steel helmet and liner.
Pile Field Cap
The olive drab pile field cap consists of a wind-resistant, water-repellent, poplin outer shell with a pile lining, a flexible visor, which can be worn up or down, and pile ear flaps with an drawcord closure. It was designed for wear in extreme cold.
Field Jacket
The M-1943 field jacket is a windproof, water-repellent jacket which is used in temperate and cold climates as the necessary windproof outer shell. It may be worn over a shirt, sweater and pile jacket, or any combination of the three.
MIL-C-1911: CAP, FIELD, COTTON, O.D. WITH VISOR (ARMY)
Military specification MIL-C-1911 initially covered a cap made from olive drab shade 7 cotton poplin with flannel lined earlap.
MIL-C-1913: CAP, FIELD, PILE, O.D.
Military specification MIL-C-1913 covers a cotton poplin, field cap with wool pile lined earflaps.