This is a 4-Speed Worm Gearbox H.E. Assembly Kit from Tamiya. FEATURES: Gearbox features four gear ratios (84:1, 216:1, 555.4:1, 1428.2:1) Gear ratio can be easily adjusted by altering the middle and final gear attachment positions 4mm dia. threaded driveshaft included Included gearbox attachment parts can be easily installed at a choice of two attachment positions Gearbox is compatible with other Education Construction items Type 260 motor included - RPM: 5040 Max Efficiency, Voltage: 1.5V Recommended Separately available 130 and 140 motors can also be attached with the included adapter H.E. denotes High Efficiency Pictorial instructions included INCLUDES: One 4-Speed Worm Gearbox H.E. REQUIRES: Assembly Medium phillips screwdriver Modeling knife (RMXR6909) Sprue cutters (HCAR0630) Long nose pliers (DTXR0300) SPECS: Length: 1.92" (49mm) Width: 1.24" (31.5mm) Height: 1.85" (47mm) COMMENTS: Keep out of reach of small children. Contains small parts. tlh 3/9/10