The Fiber Optic Extension Cables are more durable than probes and thicker. They are easier to wind, more durable and harder to break. Extension Cables for MRI are usually used from the foot of the scanner table to the control room.
EXT is for Extension Cable, 400 is for Cable Style , others are available. Cable Lengths are specified in meters 10M is for 10 meters, 12M would be for meters, Cables are cut to length. Most Extension Cables for MRI Scanners are 10-14 meters long depending on the scanner and control room location.
STM is non Magnetic ST Connector especially for MRI. HFBR is totally non magnetic for use in Head Coils or Ultra Low Field MRI. ST is a metal connector for use outside of the Magnetic field environment.

Replace STM with connector types
( ST,STM or HFBR)
( STM is most popular for MRI)
Specify Length in Meters
Specify Connector on Each Side ( replace 2 with number of meters you need
Others are available for Laser applications or high temperature