WA-Series can best be described as light duty and portable MPI Magnetizing Coils. No matter which ID Size, WA-Series Coils have an AC Output of over 4000 Amp Turns on a 115 Volt/60 Hertz Power and over 5000 Amp Turns with 230 Volt/50 Hertz Power. The 4 models of WA-Series Coils are the WA-8, WA-10, WA-12 and WA-14, with respective ID sizes of 8" (203mm), 10" (254mm), 12" (305mm), and 14" (356mm). Very economically priced. AC Coils are effective for finding surface breaking defects on work pieces with little wear, but where stress results in high load concentrations that in turn can result in component failure. Note the AC field does not penetrate the surface of the workpiece, this is called “skin effect”.