Gitzo Systematic Geared Column for Series 2/3/4 Adding a Systematic column on a Gitzo Systematic tripod is useful when you require additional height as well as quick adjustment of the working height. This aluminium geared centre column is compatible with Series 3 & carbon Series 4 Systematic tripods. The gear mechanism means heavy loads can be raised or lowered precisely & safely, & is locked & unlocked via a simple twist mechanism. The safety catch feature, when used together with recent Systematic tripods with a safety button, prevents the column from dropping out of the tripod even if it is inadvertently left unlocked.