Comparators allow the estimation of surface roughness by both touch and sight. The Elcometer 133 Ships Propeller Roughness Comparators have been developed for the specific profiles related to the condition of ships propellers over the life of the propeller. Comparators are also supplied with guidance on the report for Propeller Blades

Two versions are available, one for above water (dry dock) inspection and another for inspection work carried out underwater.