G-Class convertibles have two hydraulic cylinders lifting the top.
The seals inside these cylinders are similar to those in other convertibles and lift gate cylinders: they decay with time. Otherwise, the cylinders do not normally wear out (unless they are grossly mistreated and get damaged on the chromed shafts). Thus, with Top Hydraulics' superior seals in your cabriolet hydraulics, they will be better than brand new parts.
Top Hydraulics does not currently stock the G-Class convertible hydraulic cylinders p/n 463-805-00-01; you will have to send in yours for rebuild/upgrade service. Please contact Top Hydraulics if you need individual hydraulic lines/hoses/pipes manufactured, or if you need us to rebuild your convertible hydraulic pump.