Designed by Rat Sound to deal with the “real world” of pro audio, the SoundTools NL-4 Sniffer/Sender is the perfect tool for live environments. Test snake lines and cables when the ends are at a distance and avoid running extra cables just to test. The aluminium barrels eliminates the problem many testers face with solder joints failures and the unit will never rust. 3 simple LED’s will instantly diagnosis your cable as it tests for every possible shot, open, or cross wire in NL-4 cables. If the LED’s read all green you cable will work!