I'd just like to share this with you I did a quote for a customer that had a dog that was ping in one spot in the lounge the carpet was a 80/20 light colour the damage was really bad and had ruined the carpet really, but I got my uv torch out that I got from Russ chad not that long ago and searched for any more I could not see any with the naked eye. When I looked with the torch I was shocked to see that he had not been doing it in one place but there was at least 15 other areas that he had done his business it just goes to show that this bit of kit is invaluable a big thanks to Russ. You can get cheap ones off eBay but you get what you pay for. I would defiantly recommend this torch to anyone