Ariens 21577300 – OEM Ariens Product, Part Number: 21577300. Ariens 21577300 Ecu Ax420 12V Efi RapidTrak Pro Mountaineering 32. Ariens Part Number: 21577300 Compatible with the following Models: Ariens Pro 32 Hydro RapidTrak Mountaineering Edition Ariens Pro 32 Hydro RapidTrak Kraken Edition. We are proud to be a factory authorized retailer. We use several different carriers and choose the most economical for the item and destination based on the estimated transit time displayed. FixMyToys – A Division of Ball Equipment.