Custom screws create an airtight seal.
Nine proprietary screws manufactured exclusively for Aventi seal the Sapphire crystal case back. Stainless steel 304L is used for each screw, and triangle-shaped heads are individually pressed onto each screw head.
It was decided to use 304L stainless steel instead of 316L, the industry standard, due to its higher corrosion resistance. 304L is capable of this resistance due to its alloy composition of 18% chromium.
Every screw is machined to a size of 2.5mm to 3.4mm, then each screw head is pressed on a hydraulic press using a custom-made mould. We can achieve a perfect imprint with the hydraulic press by applying an astronomical pressure to such a small surface.
The individual screws are then inspected and polished before being moved to assembly, where they will be fastened and torqued to ensure an airtight seal within the case.