Excelsior Park Military Pocket Watch Artillery Timer

This is a very lg an unusual piece which looks like pocket watch but seems to work in reverse. Does work it a strange set up and doesnt appear to wind like a nirmal watch. But counts down or unwinds to time?? Which i believe is for Artillery timing. Excelsior was 1 of the best movement companies in the world make movements for top brands like Gallet. ---- LG at 56.8mm not counting the bell & crown. ---has spare parts compartment beside movement, have not check if any in it?? -- movement looks very clean but do not know if or when it was serviced so probably should checked. Got a lg lot from an estate and have zero interest in the military or other pocket watches. --- will take vintage chronograph parts or non working chrono in trade??? ---- serious inquiries please phone, can supply video of working thru text or fb. ---pickup in Quinte West or if I get my summer car on rd, possible meeting in Pickering or Thornhill area. -- listing other antique ww2 pocket watches by Omega, etc --- 22.00 flat rate across Canada