0.3 module teeth have load carrying capacity appropriate for most HO scale model applications, models of smaller scales and some light duty applications in larger scales (traction, speeders, etc.).
0.3mod TRANSFER GEARBOX kits - 3.125:1 ratio with 1.5mm input shaft - A miniature transfer gearbox as used in the KLW Shay powering kit. Suitable for small HO, HOn3 power from a body mounted motor driveline to underfloor location for better alignment to wormshaft of truck axle mounted gearboxes (see #211-6 series). Uses three spur gears.
The really miniature 0.3mod GEARBOX kit 50:1 ratio with 1.5mm input shaft (1.2mm optional) - A high efficiency, miniature compound gearbox for some light duty applications in larger sizes (HO traction, speeders, etc.) may be suitable. The axle fit selection covers all known small scale sizes - for those few HOn3 applications with 3.0mm axle, the miniaturization of this gearbox made it necessary to build the axle integral with the axle gear (not available in HO gauge length.