Single touch release to allow full extension or the ability to lock it out.
Extended stroke through telescoping mechanisms, usually composed of one rod and two cylinders
Vari-lift - intended for short production runs and prototypes, in applications where the exact force is important but hard to estimate in advance, such as lifting a lid slowly in a known time. In this case the cylinder is supplied filled to maximum design pressure, but equipped with a bleed port, to allow gas to be released once installed. The intention is that de the design can be over-sprung, and then the pressure reduced in stages, to optimise behaviour. If too much gas is released, a new spring must be installed, and for large quantities, it is better to order a bespoke pressure setting from the maker.