Tudor Black Bay One 89003FX_BB_B_BBX 5 mm titanium case houses 5 mm titanium case houses the Oris Calibre 400 in house movement 2446FP3824) is a delicate necklace crafted from 18 karat yellow gold The 39mm case and yellow gold accents give this watch a vintage inspired yet timeless look this Black Bay One is both reliable and stylish – perfect for everyday wear