fabric straps were used by nato forces from the mid-twentieth century as a functional and hardwearing alternative to leather and metal watch strap varieties that were available at the time. however, the two-piece strap now known as the nato strap debuted in the british ministry of defence in 1973. military watch bands had to be hardwearing and secure, and with the additions of spring bars and an added nylon strap, the nato strap provided the best security. they were also used by many professional divers since leather straps do not suit the water and they could be adapted to fit over a diving suit more easily than metal bracelets. the nato strap was initially only available in a 20mm wide ‘admiralty grey’ nylon variety, but as the style gained popularity the different british military regiments began producing straps in all manner of regimental colours. over time military men began to customise their watch straps, taking on the colours of the regiments they were in, creating the colourful stripes that nato straps are now often known for.