N2 Safety Brake
It's designed for use on small shutters and requires a 13mm and 18mm shaft.
N3 Safety Brake
It's designed for use on steel roller shutter doors and requires a 30mm steel shaft and suitable discs.
N4 Safety Brake
It's designed for use on large steel roller shutter doors and requires a 40mm steel shaft and suitable discs.
N5 Safety Brake
It's designed for use on large roller shutter doors and requires a 50mm steel shaft and suitable discs.