Styrene Gearbox Shims .010in & .015in For #5, 9, 20-Series & 40 Series & Whisker® Couplers. Any coupler using the #232 (NO.5®) or #234 Gear Boxes. Shims will need to be trimed to work with #242 Whisker® Gear boxes. 20 each per package WARNING: CHOKING HAZARD - Small Parts - Not for children under 14 years. Kadee Quality Products Co. products are not toys and are not intended for children under 14 years old.