- Introduced in May, 1875, the Crescent Park and Martyn Square grades appear to have been made for export (at least the only Crescent Park I've seen and several Martyn Squares surfaced in England - another successful Robbins experiment).
- Their style of engravings, balance bridge (with hairspring stud and wider base), and curved barrel bridge, look like a cross with the Model 70 perhaps to be more acceptable to the English market. The balance bridge and barrel bridge on these export Model 57 watches are not listed in the "Waltham" 1885 Materials catalog. Perhaps these grades should not be called Model 57s, but they share most of the same parts, including the 4-pillar plate design.
- I believe these watches are very collectible; but what really makes them interesting is the case in which they are often housed: Aaron Dennison cases.