Ruland rigid couplings are the most common mechanical coupling and used for direct power transmission or as a shaft-to-shaft connector. This rigid coupling has 1.438" x 1.438" bores, 3/8" x 3/8" keyways, 2 5/8" OD, and 3 7/8" length. The one-piece clamp style design does not mar the shaft and has a keyway for higher torque capabilities. It has precision honed bores which will not introduce misalignment or vibration into the system allowing for smooth operation up to 4,000 RPM. Hardware tests beyond ANSI standards for maximum torque capabilities and is supplied with Ruland's proprietary Nypatch® anti-vibration coating which prevents screws from loosening during operation. Nypatch® helps maintain high holding power regardless of vibration in the operating environment, allows for multiple screw insertions, and provides the necessary dissimilar material to prevent galling. It also eliminates the need to treat screws upon receipt significantly reducing assembly time. This coupling is stamped with the Ruland name and bore size for ease of identification. It is manufactured from 1215 lead-free steel to a fine burr-free finish with Ruland's proprietary black oxide formulation which creates a glossy appearance and increases holding power and corrosion resistance. This rigid coupling is RoHS and REACH compliant. It is made from bar stock sourced exclusively from North American mills and manufactured in Ruland's Marlborough, Massachusetts factory under strict controls using proprietary processes for superior fit, finish, and holding power.