Built on the sturdy Avenger platform, the Seawolf E1737018.B640.133E is also a functional success: despite the technical constraints imposed by the need to withstand pressures of 300 bars, its dimensions have been kept very reasonable and offer perfect ergonomics. To achieve this result, Breitling has chosen titanium, a light, resistant and non-corrosive metal. Breitling also commissioned researchers at the Federal Institute of Technology in Lausanne to perform numerical simulations in order to ensure perfect geometry for the case. The E1737018 B640 133E components that are critical in terms of water resistance feature dramatically outsized specifications: the watch crystal is 4.80 mm thick and the caseback 4.75 mm thick. The screw-locked crown is a patented design. The Avenger Seawolf E1737018-B640-133E also features a safety valve enabling it to balance the differences in pressure inside and outside the case. As soon as internal overpressure reaches approximately 3 bars, the valve automatically evacuates the helium built up during prolonged stays at great depths and thus avoids the case exploding.