The Bostonian is part of Gillette's New Improved line, which featured a newly designed head that was completely different from the Old Types that preceded them (although Old Types continued to be sold alongside New Improveds—in fact, that is when the original head design began to be called the Old Type.) The distinctive diamond-patterned knurling looks really sharp, and this particular example, from 1922, is in nice condition (though certainly not perfect).
What really distinguishes the Bostonian, though, is the gorgeous, shiny case. It has an internal mechanism that, as you open the case, raises the razor up to you. Really cool. It's often broken or at least hinky, but this one works great: