At last we have it, after more than 4 months of testing and improvements, it's finally here! Our Xtreme 4x4 version for the biggest and strongest dogs on walks. As a good 4x4 harness: It offers Resistance, Safety, and Comfort at the Highest Level. We have worked for months to achieve what you are seeing right now. The launch of a new XTREME 4x4 harness for dogs has been designed to offer a safe, comfortable, and durable experience over time for dogs that are very strong during their walks with pulls or where tension situations occur during walks. Do you like to go on routes, outdoor adventures, hiking, trekking, or simply walks in more trail or mountain areas with your dog?