Gibbs Ascenders can be rigged in all the standard methods for mechanical prussiks.
Assembly: Depress button on pin and pull pin out until cam swings free. Place Ascender on rope and align holes in cam and shell. Depress button and insert pin.
Convert to Free Running Mode: Remove the small screw in the black spring cover. The spring will rotate freely. Do not remove the screw in the cam. Do not try to remove the spring.
Reconvert to Spring Loading: Hold cam down and re-insert screw in spring cover.