I'm 99.99% sure it's a standard ICS M4 mechbox.
The last 0.01% is that I've never handled that specific model.
The ICS M4 mechbox is a "split mechbox" design. The lower part (gears, motor, switch, trigger) are held in the lower receiver...the upper part has the cylinder & related parts, spring, etc.
Put the two together and you end up with a standard "Version 2" mechbox. The split design allows you to take just the upper mechbox out (takes about 15 sec) and drop in a different one (typically at a different power level....or to replace a stripped piston quickly at a game). With a "traditional" version 2...you've got to take the whole rifle apart, take the mechbox apart, swap the parts and reassemble the whole thing just to test (takes a lot of time in comparison).
Aside from one or two specific ICS parts...the mechbox can use standard V2 parts. Several version 3 parts are compatible with version 2. (Lots more info elsewhere on that...search around on here and other forums)
Last edited by m102404; July 17th, 2009 at 08:47..