Great product! Hello, I am a person with Parkinson's disease and severe depression, my dog accompanies me everywhere. My dog is now 14 years old and cannot walk. I had to find a way to build a car so we could go to the airport and fly home to my daughter. After ordering this set of wheels, I received a 2" x 4" sheet of plywood and a few small screws. I built a cart that wouldn't be too bulky but very durable for my 105 lb dog to take with me. The wheels roll very nice and smooth, I had a great ride through the airport, after arriving at their destination my grandkids even used a cart to roll down the driveway and have fun! My dog made the trip amazing and we will use the trolley to get home. I'm very glad I bought this product and it's really amazing!