Check the listing for details. "New" Autotrol Red Output Gear Timer Water Softener Parts. Condition: Open box. Listed at 39.95 USD. "New" old stock Autotrol Red Output Gear (Much finer teeth then AP420B52) Water Softener Parts. No longer manufactured. See detailed images of part offered in this listing. I acquired an entire lot of Autotrol new and used parts and will be listing more. Auto Regeneration trigger FAILURE can be caused by this Output Gear ( when the 2 1/2 over hang teeth snap off ), and / or the # 8 Black gear that drives it strips ( and sometimes the post that holds the # 8 gear breaks off housing )INSTALLATION TIP:To remove the Output connector from the Output Gear, you must Pull really hard.And the output connector is then Pushed into the new part ( also requires a lot of force.. it's a tight fit ).Noting the Gear and Connector are "keyed" and only fit one way (so you can't do it wrong).