The Bird Model 43 is a thoroughly engineered, portable, insertion-type instrument designed to measure both forward and reflected CW power in coaxial transmission lines. It gives accurate RF power flow readings under any load conditions. The Model 43 THRULINE wattmeter is comprised of a line section and direct-reading 3 scale meter housed in a rugged, corrosion-resistant aluminum case. QC (quick change) type connectors and a full range of plug-in measuring elements (ordered separately now or later to meet your existing needs) give the Model 43 amazing flexibility. Two extra elements can be stored in the housing, one on each side. The Model 43 is easy to use and simple to service in the field.