Probe is for models 50B, 51B, 52, 54A-RC, 54A-BP, 56, 57, 58 and 59. Waterproof connector attaches to 10, 25 and 50 foot cables (Nos. 628-500-14 to 628-500-18). Probe’s design compensates for pressure which ensures deep water operation without errors. Built-in weight eliminates attached-weight cable problems. Membranes and KCl solution are included. Order cable separately. Warranty: One year.