Rolex’s micro-adjustable bracelet extension for the Submariner is called Glidelock. It is built into the clasp and lets the wearer lengthen or shorten the bracelet in small increments without tools.
The system was introduced on modern Submariner models as part of Rolex’s effort to make a professional dive watch easier to fit over changing wrist conditions and, when necessary, over a diving suit. Depending on the generation, Glidelock provides up to 20 millimetres of adjustment in 2-millimetre steps.
Glidelock is not the same as Fliplock. Fliplock refers to the folding safety extension used to add length for wearing the bracelet over a wetsuit. Easylink is Rolex’s comfort-extension system found on many other models; it generally provides a quick extra length rather than the Submariner’s graduated clasp adjustment.
Oysterlock is another commonly confused term. It describes a safety feature of Rolex clasps, not the Submariner’s micro-adjustment mechanism. The name Glidelock therefore identifies the specific tool-free, incremental adjustment system.