80% Polyester, 20% Cotton. Fabric: Stretch. 245gsm. Design: Contrast, Reflective. Hammer Loop, Pre-Bent Knees, Reinforced Knee, Tool Holder. Pockets: 2 Side Pockets, 2 Back Pockets, Flap Closure, Knee Pockets, Internal, Hook and Loop. Conforms to Safety Standard: EN ISO 20471 Class 2. Ref: UTUB621