Supco MAG1YL Appliance Magjumper 30 Vac Magnetic Test Leads MAGNETIC TEST LEADS - Magjumper magnetic low voltage detector and troubleshooter. Ideal for low voltage troubleshooting recessed terminals. PREMIUM REPLACEMENT - Supco parts are designed to meet or exceed OEM specifications. HIGHEST-QUALITY PARTS - Supco parts are built to last and a popular choice among repair technicians and DIYers.