The National Time HMR series clock mechanisms employ worm/ worm gear drive technology to provide smooth and continuous advancement of the hands. In addition, this technology protects the clock mechanism from natures harshest elements such as wind shear, snow and ice. This is the 1st series to incorporate National Time's cast aluminum gear housing design. The standard mechanism is driven by a permanent magnet, 115V 50Hz or 60Hz synchronous gear motor. The HMR series mechanisms offer mounting options to suit all applications with dial sizes to 72" diameter. Custom shaft lengths can be provided to meet specific project requirements. Remote manual switch or automatic clock controls are used for resetting the units to the correct time following power outages or daylight savings adjustments. HMR series mechanisms are compatible for synchronization with the NIST atomic clock when used with the MC100-GPS or MC100-LAN interface options.