The Collins 312B-4 houses a speaker, an RF directional wattmeter (with 200/2000 watt scales) and a hybrid-type phone patch. 10 x 7.75 x 12.25 inches 8.5 Lbs.
The 312B-4 is a great match for your KWM-2.
Pre owned, in good condition see photos. Item NOT tested.
Sold as is, no refunds.