#5 (NO.5®) Metal Couplers - Medium Centerset Shank. This industry leading coupler features an all metal standard coupler, and #634 standard centering spring and comes complete with and insulated draft gearbox and lid. The NO.5® Magne-Matic® Metal Coupler may be mounted with the included #232 Gearbox or with other manufacturers cast-on coupler pockets. The 148 Whisker® Coupler is equivalent to the NO.5® Metal Coupler. It is not recommended to use a metal coupler directly on a metal surface or in a metal draft gearbox to avoid possible electrical crossover and shorting that may cause damage. Use the provided insulated gearbox or insulated #28 coupler. Two pair per package Package Includes: (2) Pair NO.5® Metal Couplers - Medium Centerset Shank (2) Pair #634 Centering Spring NO.5® Style (2) Pair #232 Gearboxes (2) #622 Knuckle Springs NO.5® Metal Coupler Features: Material - Metal Shank Length - Medium (9/32") (center hole to back of coupler head) Coupler Offset - Centerset Knuckle Spring - #622 Centering System - Standard Shank Centering Spring - #634 Centering Spring NO.5® Style Head - Standard Head Works In Place of - #58, #28, #118, #119, #148, #158, most medium centerset "clone" couplers Works With - #213, #232, #234, #242, most manufacturer cast-on draft gearboxes #232 Plastic Draft Gearboxes & Lids Features: Material - Insulated Plastic Dimensions - 29/64"L x 19/64"W x 7/64"H Works With - NO.5®, #58, 20-Series and all Whisker® Couplers Mounting Specifications: Mounting Height - 29/64" Centerline - 25/64" Trip Pin Height - 1/32" Center Hole - 2-56 Insulated Screws are the most commonly used. (Screw length will vary) Side Holes - 0-48 Self-Tapping or 0-80 Machine Screws. (Screw length will vary) 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.