= Geometric Anti-Spring Filter =

A '''G'''eometric '''A'''nti-'''S'''pring filter (often called '''GAS''' filter) is a mechanical stage of the KAGRA suspensions realizing vertical spring with a low resonant frequency.

The GAS assembly is embedded in 3 types of mechanical stage.

 * Top GAS filter
 * Standard GAS filter
 * Bottom GAS filter



== References ==