A device is used to hold an optical element, in particular one made of a crystalline material, in particular of CaF2, while the optical element is being coated, in particular by the vapor-deposition of at least one functional layer in a vacuum coating plant. In another embodiment, the film structure comprises a second skin layer comprising a thermoplastic polymeric material and an effective amount of a high-melting incompatible additive to suppress cavitation in said second skin layer, wherein the second skin layer is exterior to the second side of the core layer. A second motor is mounted between the two frame members and coupled to a gear set. The server is configured to perform, over a long-range communication protocol, two-way communication with the communication system located within the building, is configured to manage access to the keysafe, and is configured to handle reporting related to access of the keysafe. The memory chip has a data bus interface having a number of bits.