These three share the identical ugly uniform shiney crayon brown glaze as well as ugly gaps and bumps in the pinhole top, and the flat inner skirt bottoms. The signal is closest to U-268 and the large cable appears to be U-931A . U-931B has a glazewelded inner most skirt. This one does not. Smaller specimens of signal and cable styles may have glazed pinholes which is the exception to most larger styles. See the next picture for a shot of the bottoms.