3-piece L090 series coupling set includes two coupling halves and an NBR rubber insert. 3/4" bore with 3/16" keyway and set screw on the matching coupling half. 1" bore with 1 /4” keyway and set screw on the matching coupling half. Interchangeable with Lovejoy, Martin, Browning, TB Woods, and other L-jaw couplers. It is made of high-strength HT250 steel with greatly improved service life. 3/4" to 1" L090 3-Piece L-Jaw Coupling Set & Buna-N NBR Rubber Spider for Log Wood Splitter