Horizon Fitness Advance 300 (2004) Treadmill Horizon Fitness Updated September 15, 2021 19:24 For the 2004 Horizon Fitness Advance 300 Owner's Guide, please click here. For the 2004 Horizon Fitness Advance 300 Exploded Diagram, please click here. Was this article helpful? Yes No 0 out of 0 found this helpful Have more questions? Submit a request Related articles How to Replace the Running Belt and Deck on a Treadmill. Horizon Fitness Advance 500 (2004) Treadmill Horizon Fitness Omega II (2004) Treadmill How to Calibrate a Treadmill Comments 0 comments Please sign in to leave a comment.