I've never seen a 3/0 Maximus, but Waltham did make a 3/0 Riverside, 21 Jewel with Gold center wheel.
This watch may be 19 Jewels because the pallet is not capped up and I don't think it has a Jeweled Main Wheel, although I've not taken it down to check.
Good question. From carelessly scanned old photos I thought I had an original Maximus movement Waltham ww. that is actually marked only as a Diamond. Thus the too brief question if Waltham ever used a Diamond Maximus in their early ww as they did with the Opera? artb
Waltham was a very big American pocket watch manufacturer in the 19th century, located in Massachusetts. It died out in the 20th century, and is today owned by a Chinese company that produces cheap quartz watches under the Waltham name.
Some of the pocket watches it produced in the late 1800s show true excellency, and were actually much superior to the Swiss watches of those days. nox player for pcjiofi.local.html
This particular watch features an old-timey porcelain dial and, no doubt, a fine handwound movement. You should know, however, that it will need some work done to get it wearable.
HI I have a Waltham riverside Maximus wristwatch .I has a Os size 19 jewel movement and gold filled Dennison case.It is very good condition
running very well keeping good time.I purchased it in 2018 off eBay.