Tudor Black Bay 58 GMT Jubilee 39mm 7939G1A0NRUOverview The Tudor Black Bay 58 GMT reference 7939G1A0NRU the Coke is the most technically ambitious watch in the BB58 line. A true flyer GMT in a 39mm case is a meaningful engineering achievement: the local hour hand adjusts in one hour increments without stopping the movement, a complication that Tudor has packaged into the same slim profile as the standard BB58. The 39mm case retains the BB58s defining proportions: 11. 7mm thick, with a domed