Another one that has illuded me until now is the M-2251 seen on the left. Much like the M-2255 but without the flared bottom. The top shell is shared by no less that four M- Numbers. As an added bonus, it has two blue jean seems from the early no name Thomas days. The no name piece on the right was believed to be M-2340 but looked too large. When I got it home, a side by side comparison confirmed it wasn't M-2340 but what is it?