The wool uniforms are two - piece ( shirt and pants ) designs that lack colored piping on the shoulders and edges of the pant leg cuffs and have a raised collar .
The wool uniforms most main cast members wear from the third season onward .
The wool uniforms , which most main cast members wear from the third season onward , are two - piece ( shirt and pants ) designs that lack colored piping on the shoulders and edges of the pant leg cuffs and have a raised collar .