Limited Editon of 500 Pieces. Briston Watch Clubmaster Traveler Worldtime GMT Limited Edition GMT 20842.SA.TW.9.NNB. It is this spirit, combined with its watchmaking DNA, that gives Briston watches its unique style. Working with innovative materials, such as cellulose acetate, and colours give Briston watches their distinctive look. Briston watches also offers the perfect balance between a contemporary timepiece and a chic accessory, casual but resolutely and thoroughly accessible.