Kettler skylon 3 cross trainer kettler skylon 3 cross trainer offers an impact free workout with a smooth mechanism to ensure a comfy exercise session a heart rate light programme measures your heart rate and gives a the 3 light system to indicate whether you are working healthily too hard or not hard enough the back lit computer has 9 functions on continuous display to track your workout as you exercise an integrated pulse control receiver records your heart rate and the adjustable br