Application? AM133924 Double Deck Drive Belt Tightener Pulley is suitable for John Deere LX280 LX288 LX289(48C deck) GX255 GX325 GX345 GX355 48C and 54C Mower Deck. Function? Replaces the aging double pulleys on mower decks to help maintain a safe ride and make mowing easier. Material? Constructed from heavy- duty steel with high strength, it is sturdy enough to resist impact and meet your need, durable to use for a long time. Replacement? Directly replace JD OEM part number: AM133924, AM127594, AM125668, Manufactured from OEM Specification.