alarm systems, cctv systems, access control, doorphone systems, PA systems, fire systems, ip camera. Inverters. Solar panels. solar controllers. Batteries. Surge Protectors. Emergency power sources. Charging device.

Screw with the inner hexagon M8x20 of stainless steel

Stainless steel provides many years of reliability, protection against external factors (including corrosion).
It will work great in conditions where reliability and durability are needed.