This gas spring replaces the original 160-0004 gas spring supplied by Lancair for the main gear on Legacy models.  This is one spring, two are generally needed per aircraft.

This gas spring is an important part of the emergency extension system, it holds the gear overcenter in the event of a hydraulic failure.  All gas springs degrade over time, its important to check for proper function of the gas spring in-flight at least annually to ensure it has enough charge to lower the nose strut completely.  It is even better to remove the spring and test it on a bathroom (or similar) scale during annual.

Always install gas springs with the rod end down, this better prevents leakage of the gas charge and properly lubricates the seals inside the unit.