Mackie MTest-1

Mackie MTest-1 — Universal Audio Cable Tester
The MTest-1 is a universal cable tester with intelligent pin-matching to test virtually any audio cable — whether store-bought or home-built. 
It includes connectors for the 7 most common audio cable types: 1/4″ TS/TRS, 3.5 mm TRS, XLR (3-pin), RCA/phono, speakON, MIDI (5-pin DIN), and banana/continuity.
Even for cables with mismatched ends (e.g. XLR ⇄ 1/4″ TS), the MTest-1 automatically detects the connector types and matches the pins for accurate testing. 
For less common connectors, you can use the included signal probes to check continuity manually. 
A bright LED readout gives instant visual feedback — continuity, proper pin connections, and grounding status are clearly shown. 
Powered by a single 9-volt battery (with onboard battery-check function), so it's portable and ready for use anywhere — studio, live stage, or on the road. 
Built with a rugged steel chassis (“Built-Like-A-Tank™”) for durability — ideal for frequent use in studios, live rig setups, or touring.