This shirt comes with several options for the back

Flatlock seams for comfort

but is 100% Poly shirt

30/1 fine jersey tank with racer back styling

I Co Athletic Performance T-Shirt. This shirt IS approved for PT Personalize:Add Custom Call Sign This shirt comes with several** THIS SHIRT IS AUTHORIZED TO BE WORN FOR PT ** DESCRIPTION: This is a 4. 7 oz., 100% filament polyester t shirt with wicking properties and antimicrobial properties. CARE INSTRUCTIONS: For longer garment life, turn inside out and wash cold, tumble dry low or hang dry. Do not use high temperatures. Do not use bleach or pods with fabric softener in them. If the garment is going to be ironed, use low temp, and cover printed area with craft paper.