Wikipedia:K-72 trailer

The K-72 trailer, manufactured by the A. J. Miller (Auto Cruiser Trailer Co.), was a house trailer used by the U.S. Army Signal Corps during and after World War II.

Specifications
The A. J. Miller  built the K-72 trailer, which has two axles, one on each end. Its net weight is 7,500 lb and it is 232¾ inches long, 124½ inches high, and 93¾ inches wide. It has four windows including the one in the door.

Use
The K-72 trailer primarily was used to house the operators of the SCR-527 radar.