An OTDR is the optical equivalent of an electronic time domain reflectometer. Time delay can be determined using a device such as an "optical time-domain reflectometer". Features a Time-domain reflectometer (TDR) with a granularity of 30 meter. In 2012 Megger won an award for its TDR1000/3 time-domain reflectometer. The equivalent device for optical fiber is an optical time-domain reflectometer. The D3 Neutron Reflectometer is designed for examining surfaces, thin films and interfaces. PLATYPUS is a time-of-flight reflectometer built on the cold neutron source.