The 465M is essentially a 100MHz bandwidth scope in a 455 cabinet. Construction methods of the 455, 465M and the T900 series are similar. Semiconductors are not socketed as they are in the other 400-series portable scopes, which contributes to greater reliability. The front panel layout of the 465M is nearly identical in appearance and function as that of the 465. Although the vertical preamplifier and trigger/sweep unit are plug-on modules causing one to guess that there would be other implementations of those functions, there were none. What you see is what was made. There never was a single-channel or single timebase module made, although some may have been originally on the drawing board. Whether or not these models were more rugged than the original 465 is unknown. In the Oklahoma City Service Center, we saw a lot of 465Ms come in for warranty service, primarily from the FAA who had bought into that model in a big way. But what comes in the door is no indication of reliability as we would be comparing a glut of new 465Ms that were shipped into the FAA depot in OKC compared to an established customer base of 465s.