Custom Rotary Switches, Ground Fault Analyzers and Strain Reliefs Since 1969 - Multi-Tech Industries, Inc. strain reliefs, strain relief, rotary switches, rotary switch, rotary limit switch, keyswitch, push button switches, pushbutton switches, ground fault detector, electrical switches, rf power components, relay switches, Tech Laboratories, Multi-Tech Indust Multi-Tech Industries manufactures a full line of Custom Rotary Switches, Ground Fault Anaylyzers and the Gripmaster Strain Reliefs, along with the capabilities to manufacture, assemble and test custom specified prototypes or components.