it was the first to feature a unidirectional bezel with a dual scale for depth and dive time to calculate a safe ascent without decompression stops

Glass:Sapphire crystal Antireflection treatment on one side

And if you want

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MAT Watches - SAR UTC (Orange) Tissot it was the first toCase: Material: Stainless steel 316L Dial: black with hands and markers in Super Luminova BGW9 Glass: Antireflective sapphire crystal, 3,8mm of thickness Caseback: Stainless steel 316L Crown: Screw in, diameter 9mm Diameter: 44mm Thickness: 15,5mm Movement: Caliber: ETA 2893 2 Swiss Made Frequency: 28800 h Ruby: 21r Power reserve: 42h Winding: Automatic, H+M+S+Date+UTC24h