Information from Kadee's website: This industry leading coupler features Original Style Head Medium Centerset Plastic Couplers, and #850 O Scale centering spring and comes complete with Plastic Gearboxes and lids. The #804 Plastic Coupler may be mounted with the included #817 Plastic Gearbox or #818 Metal Gearbox (sold seperatly), #819 Extended Metal Gearbox (sold seperatly). 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. O-Scale Simple Drop in Design Trouble Free Operation Compatible with All Kadee® O-Scale Couplers World-Renowned Quality & Performance They just Last & Last & Last... Package Includes: (2) Each #804 Original Style Plastic Couplers - Medium Centerset Shank (2) Each #817 Plastic Gearboxes & lids (3) Each #850 O Scale Centering Springs #804 Plastic Coupler Features: Material - Plastic Shank Length - Medium (47/64") (Knuckle pulling face to center hole of Draft Gearbox) Coupler Offset - Centerset Centering Spring - #850 O Scale Centering Springs Knuckle Spring - #845 O Scale Knuckle Springs Head - Original Style Head Works In Place of - #740, #745, #800, #801, #805, & #816 O Scale Medium Centerset Shank Couplers Works With - #817, #818, #819 Draft Gearboxes #817 Plastic Draft Gearboxes & Lids Features: Material - Plastic Dimensions - 25/32"L x 1/2"W x 7/32"H Works With - #740, #742, #745, #746, #747, #800, #801, #804, #805, & #816 Couplers Mounting Specifications: Mounting Height - 25/32" Centerline - 1 1/16" Trip Pin Height - 1/16" Mounting Holes - 2-56 Insulated Screws are the most commonly used. (Screw length will vary) Recommended Tools: #812 O Scale Coupler Height Gauge #231 Greas-em Dry Graphite Lubricant #237 Coupler Trip Pin Pliers #240 Double Headed Pin Vise #241 Dual Tool Manual Uncoupling Tool and Spring Pick #246 Tap (2-56) and Drills (#50 and #43)
