"...I have tested the pre-production V2.0 PowerMAX, and all the dimensions are the same as the first version except the wheels.
The wheels are the same diameter, but the 6.5mm gauge wheels have a .51mm deep RP-25-profile flange and 1.02mm tread width. It is both a better looking and better tracking wheel. (The older wheel had a simple "pizza cutter" profile which, on some assemblies, could induce some wobble in the chassis if the unit ran on the edge of the flange.)
The 9mm gauge wheels have an RP-25 flange, but wider tread to negotiate N-standard gauge flange-ways. ..."
6.5MM & 9MM PowerMAX! Comparison
The SEARAILS v.2 PowerMAX! is designed for use in Diesel, Gas/Electric, and Battery locomotives. A US Patent has been submitted for application.
It has a 6volt 60:1 gear ratio motor driving NMRA RP-25 standard wheel profiles. There is a center pivot accessory for rotation, and "butterfly" cover plates for use in fixed position applications.
There are two gauges available; 6.5mm and 9mm.
Gauge is the dimension between parallel track centers.
The 6.5mm gauge is used for Z (1:220) scale standard track, Nn3 (N (1:160) scale Narrow Gauge track, and HO2 (1:87.5) scale Narrow Gauge track.
The 9mm gauge is used for N (1:160) scale Standard Gauge track, and HO3 (1:87.5) scale Narrow Gauge track.
The PowerMAX! v.3 is specifically manufactured for STEAM LOCOMOTIVES only.
It is identical to the v.2 but its wheels are quartered for steam driving rod attachment as in the adjacent specification.