Walcott Radio DL1000 Overview
Dummy loads like this are used on base station setups, or test benches when you want to measure power output without actually broadcasting your signal. But more importantly is making sure you are using an exact 50 ohm test variable that won't change like an antenna system might. When measuring power output, if you're looking for accuracy, you do not want the antenna system with all of it's potential variables to affect your reading. Requires mineral oil sold separately (typically hardware / automotive stores).