This listing is for one each 26137 Locking Nut and 26145 Schnorr Washer used to mount the disc blade plate to the pinion shafts on the cutter bar on the Gribaldi Salvia DM Series disc mowers There would be one nut and washer used on to mount rotor disc, a 5 disc machine would use 5 sets, a 6 rotor machine would use 6 sets and so on. This is an OEM replacement part see positions 2 and 3 (Arrows) in the exploded view drawing. We also have other parts for this disc mower in our online store. We sell many replacement parts for the most manufacturers of tillers, finish mowers, spreaders, 3-point hitch hay tedders and sickle bar mowers. If you don't see the parts you need listed please contact us we would love to earn your business. We are listing new items frequently so please check our store often. Part Number: 26137 / 26145 We stock a wide variety of replacement parts for Agricultural Equipment please contact us if you have any questions or if you would like more information.