99.9% sure the clear Thompson has plastic gears like the one found at the bottom of this list.
http://palcosports.com/catalog_produ...list_by_power=
The Cyma has a metal gearbox with metal gears.
99.9% Cybergun is a rebranding company that owns certain trademarks for airsoft use I don't believe they really do make anything.
Here is what I did to get my Cyma M1A1 Thompson Authentic.
1. Wood Kit (you will need access to a dremel:
http://www.ebairsoft.com/authentic-t...ood-p-933.html
2. Kerr Sling:
http://www.ima-usa.com/product_info....oducts_id/1440
3 Some knowledge easily found by using Google:
http://www.rookscastle.com/tutorials/disassembly.html and
YouTube - How to Disassemble the AirSoft Thompson
4. Some mags ( I use the KA 110 rounders):
http://shop.ehobbyasia.com/catalogse...mpson+magazine
Here's what I am doing for an "authentic" military style M1928 (work in progress):
1. Wood kit plus:
http://www.ima-usa.com/product_info....oducts_id/2388
2. Dremel out the top of the receiver and move the cocking handle up there it's stricly a "decoration".
3. Fill in the side of the receiver where to cocking handle was with a thin piece of metal (I used old press plates from a letter press and painted it). Not 100% happy with the outcome of this as yet.
4. "glue and shape a very similar looking thimble (buy a few) to the cocking handle to look like this:
