ff, I have two Cateye double wireless and it is great, except when the battery goes then you have to re-sync it with the main unit. I've ridden with groups and had no problem and in the computrainer group, where we're only two feet apart, still no problem with other computers or heart rate monitors. Pricy at $199 and that's if you can find one in the city. Seems Cateye is way behind in back orders for this unit.