Check the listing for details. Progressive Electronics Tempo 521 Irrigation Tester, Wire & Valve Locator. Condition: Used. Listed at 250.00 USD. Model 521 Tempo Cable and Wire Irrigation Detector. Good used condition. Tested and working. See photos. The Model 521 Cable Detector (most commonly known as the Tempo Communications 521A or the upgraded digital Tempo 521E) is an industry-standard professional underground wire and valve locator. It is widely used by irrigation and utility technicians to trace buried control wires, locate lost solenoid valves, and pinpoint cable faults or breaks