Specifications: Case Specifications: Stainless Steel Color : Silver Case Diameter: 43.0mm -Lug to Lug: 48.5mm With Bezel Thickness: 12.5mm (without caseback) Lug Width: 20mm Water Resistance : 300 Meters Helium release valve Included: Top Double Domed Sapphire Crystal (Blue Anti-reflective Coating on Inner Surface) 1 Crystal Gasket (more upon request) Sapphire Caseback (With Blue Anti-Reflective "AR" Coating on Inner Surface) Crown (Screw-Down) Pair of 20mm Spring bars Parts Compatibility: Fits SKX007 Chapter Rings Fits SKX007 Flat Bezel Insert 28.5mm Dials for Seiko NH Movements For Movement Types: NH34 ,NH35, NH36, NH38, NH70/71/72 NOTE: Sapphire Crystal is provided UNINSTALLED so you may install your chapter ring first. Comes with .4mm spacer for between the dial and chapter ring (allowing the crown stem to become centered within the crown tube) and so that you can also use thicker (up to .8mm) custom made dials (without the spacer) such as those that are laser engraved with layers.