Olive Drab O NEG O- NKA Blood Type OD Green Embroidered Fastener Patch Size: 1.8 x 1.8 inches / 4.5 x 4.5 cm (aprox +/- 5%) High quality patch perfect to be worn on uniforms, tactical equipment, vests or jackets Double-sided Touch Fastener backing (hook and loop) NKA = "No Known Allergies"