Master key Using a Nemef master key system, you can control who has access to which areas without the need for large numbers of keys. Nemef offers a choice of several conventional or reversible key profiles, with pining determining the variations and levels within the master key system. Distinguishing between protected and unprotected profiles, we ensure not only that the system is secure, but that it responds to the needs of its users. Our flexible solutions allow you to apply a master key system to doors of assorted thicknesses with an array of furniture. Our standard cylinder length is 60mm, with adjustment in increments of 5mm in either direction upon request. Whether for housing, healthcare, commercial or any other application, Nemef can help you find the master key solution you are looking for.