ROLEX REF. 16600 SEA DWELLER 4000 CUSTOMIZED BY BLACK LIMITED EDITION PVD STEEL Rolex, "Oyster Perpetual Date, Sea Dweller 4000ft = 1220m, Superlative Chronometer Officially Certified," No. 22 / 50, Ref. 16600. Made in the 1990s, customized by Black Limited Edition in example of 50 pieces. Fine, center seconds, self-winding, water-resistant, stainless steel PVD-coated diver's Chronometer wristwatch with date, helium escape valve and a stainless steel PVD-coated Rolex Oyster Fliplock bracelet. Three-body, polished and brushed, screwed-down engraved case back, graduated unidirectional revolving black bezel for the decompression times, Triplock winding crown protected by the crown guard, gas-escape valve at 9, sapphire crystal. Black with luminous white gold round, triangular and baton indexes, outer minute/seconds division, aperture for the date. Luminous white gold skeleton hands. Cal. 3135, rhodium-plated, 27 jewels, straight-line lever escapement, monometallic balance adjusted to temperatures and 5 positions with Microstella timing screws, shock absorber, self-compensating Breguet balance spring, Microstella regulating screws, hack mechanism.