Bird 4210A100 - RF Wattmeter Movement Kit, 30µA
The Bird 4210A100 is 3-1/4" square RF Wattmeter pre-mounted in an aluminum case. When combined with the appropriate 7/8" line section, QC connectors, and elements, you can assemble it to a custom rack mount or use it as a benchtop wattmeter.
Please note, elements, line sections, and QC connectors are sold separately. Compatible elements can be seen in tables 1, 2, 3, 3A, 4, and 6 of the document linked here.