Marked: "DAYRAD Tube Checker / Mfd. by the Radio Products Co., Dayton, Ohio. / Licensed Under Weston Patent 1704566 Type B". Includes leather carrying strap. Tube tester designed for A.C. plug in ...

Robot vacuums are marketed as convenient household aids, taking on the task of floor cleaning so you don't have to. They glide across surfaces, collecting dust, crumbs, and pet hair, with some models ...

Abstract: As a potential development direction of future transportation, the vacuum tube ultra-high-speed train (UHST) wireless communication systems have newly different channel characteristics from ...