Listing is for fifteen (15) each right and left hand tines for a John Deere Model 550, a full set, codes PT8444 & PT8445. The PT8444 and PT8445 are tines with a "L" shape and the PT8446 and PT8447 are tines with "C" shape (sold in our eBay store). This listing is for the PT8444 & PT8445 "L" tines, which can be used to replace either style, once mounted they are completely interchangeable. Both have two mounting holes roughly 2-1/4" on center. This is a full replacement set for a John Deere Model 550 tiller