I would say it is meant about the insulation and lining

featuring a zipper and button closure

featuring button closure and pockets

Features a button closure and two front pockets

Vintage 80's Women Military Smock Shirt Size:M I would say it isThis is a vintage 80's military shirt in green, made of cotton. Features pullover design with button closure on the shoulder. Vintage condition level 5 (as new)MODEL is 5ft (167cm), 132 lbs (60kg ) and she wears the size available. SIZE: Estimated fit: size M. To be sure it would fit please check the measurements below. FLAT Measurements (unstretched): Length: 26 1 2 " 67. 5 cm Armpit to armpit: 21 " 53. 5 cmShoulder to shoulder: 16 1 2 " 42 cmSleeve: