Trying to Find the Right Harness

I've been researching harnesses online. I want a super indestructable one if there is such at thing. So far dh and I have taken Wally to two pet stores and didn't have any luck. I will be making an online purchase. For now we clip Wally's harness together with a carabineer. We also clip the carabineer through his collar.

It's starting to get to hot to walk a long distance during the day with the dogs. I walked them about 2 miles today. When we returned both dogs lay down by the door and didn't move for about a half hour. The long walk will have to be moved to evening.