#242 HO Scale Universal "Black Box" Snap-Together Insulated Gearbox & Lids
Precision engineered to work with Kadee® NO.5®, 58, 20-Series and 40-Series & All Whisker® Couplers.
10 pair per package
2-56 screws are the most commonly used for center hole.
Screw length will very depending on the mounting situation.