I bought mine at the Home Depot in Halifax about 6 months ago... I think it was a surplus item as I haven't seen it on the shelves since. Mine is not a "Park Zone" but it uses ultrasonic technology to gauge the distance. However, I have it turned off as it has a tendency to beep in the middle of the night when the car is in the garage!!! Sometimes it works great... and other times not so good - if I depended on it 100% I would have driven into the family room a few times! Save yourself $20 and get a tennis ball.