Similar to Nabrico Part #: RB-12. A: 16.65″. B: 6.8″. C: 12.5″. D: 7.75″. E: 6″. F: .83″. G: 1.33″ R. Maximum Wire: 1″. Weight: 136 lbs. These are the finest high-load carrying, free-rolling roller buttons that have ever been designed and are manufactured in sizes to suit the needs of boats, seagoing tugs and ships. Precision machined parts have working parts coated with an extremely hard coating – 70 Rockwell C-Scale – which is corrosion resistant. The buttons will not freeze up as most do, because they are closed at the top. The air pocket formed on the inside, makes it practically impossible for water to enter the working parts. Before shipment, the roller buttons are completely lubricated and should need only occasional attention after installation and use.