The #232 Plastic Gearboxes & Lids are the same gearboxes included with all No.5®, #58, and 20-Series (medium & long shank) couplers. They also work with all medium and long shank Whisker® couplers. These gearboxes make great replacements for manufacturer's molded-on gearboxes and make adapting Kadee® couplers to your models a breeze. Coupler Mounting Boxes with Lids. 20 pair bulk pack.