We have a rescue Harrier. Notorious for turning 'off' his ears and venturing off our 16 acre property into our neighbor's property and also on to the main road. We spent a lot of money on our fencing to try and keep him within our boundary and nothing worked. After much deliberation and talking with Colin at the Dog Line, we purchased the Dog line and installed as per the instructions and videos provided. Once installed, we followed Colin's training tips. I would say within the first 2 days, our dog quickly learnt where he could venture. The blue flags are a great idea as well. So its been about 1 week and our once lead only Harrier is able to run free on our property. Its wonderful and highly recommend this product. The dog stays about 20 metres from any fence as he sees the flags, he avoids those areas. He checks in with us every 15-30 mins whilst he does zoomies around the property. Would highly recommend the product for anyone that has a problem dog, as it is working a treat with us. Very happy customer right here! :)