Bremont Watch Supermarine 300M GMT Green Black Rubber SM40-GMT-SS-GNBK-R-S. Designed around the principles of Air, Land and Sea, Bremont watches are built to perform in any environment. It is for this reason that they use the highest quality materials and watchmaking techniques available in the construction of our timepieces. Inspired by the significant history of watchmaking on these shores, Bremont are determined to build a contemporary, luxury watch company in Great Britain.