Nagra   

Name of a portable location recorder made by Kudelski. Despite the availability of portable DAT recorders, the stereo Nagra IV,  which uses 1/4 magnetic tape is still the industry standard. 

This is because it is extremely reliable and relatively easy to repair and maintain. 

 
The Nagra uses the Pilot tone system to maintain constant speed with most recordists also using timecode as well for synchronization.  The Nagra has built-in phantom power. See modulometer for a description of th metering system.