Male and Female. One for each end of the cable. Tells you if the cable is good and both ends don't have to be in the same place. Great for situations where the cable is already in place.
Also, use the Female tester alone to check 6 circuit par bars with ease. Threads removed - just push it onto the connector. 6 LEDs tell you if there's a problem, green for "good," no light for "bad" and red for a short circuit. Powered by a 9v battery.