Gas springs provide controlled motion and speed for elements, such as lids and doors, that open and close. They typically rely on the fluid dampening of a gas such as nitrogen in the cylinder.  Important performance specifications to consider when searching for gas springs include absorber stroke, compressed length, extended length, maximum force (P1), and maximum cycles per minute.  Absorber or spring stroke is difference between fully extended and fully compressed position.  Compressed length is the minimum length of shock (compressed position).   Extended length is the maximum length of shock (extended position).  The maximum rated force for shock absorber or damper, referred to as the P1 force.  The maximum cycles per minute are the rated frequency of compression/extension cycles.