Pico Shrouded 4mm to 4mm Leads, 1000V CAT III, 0.5m Black or Red The TA308 (RS 136-5317) is a black double insulated 0.5 m lead with shrouded male 4 mm banana plugs at each end, suitable for test environments that require 1000 V CAT III rated equipment to be used. The TA309 (RS 136-5318) is a red double insulated 0.5 m lead with shrouded male 4 mm banana plugs at each end, suitable for test environments that require 1000 V CAT III rated equipment to be used.