Brand new XXL K9 Sport Sack Rover backpack, complete with 3in booster block. I put my dog in this once and realized that she’s too heavy for me to carry around. This is perfect if you have a large dog and want to take them with you on all of your adventures! This backpack has been rebranded as the Kolossus Dog Carrier on the K9 Sport Sack website. Designed for dogs with length 26-29in and girth up to 40in. The booster block extends the length sizing and is perfect if you have a growing pup! Brand description below: XXL backpack: “Introducing THE biggest bag on the dog market. The Rover has been developed over the last two years to be the premier big dog carrier on the market. With sizes ranging from Large to XXL, this bag is the perfect fit for big dog lovers. The Rover is great for those looking to take their bigger dogs on adventures in ways they never thought of before.” Booster block: “If your dog is in between sizes, has a wide body but short in length, or is still growing, the Booster Block fits snugly in the bottom of your K9 Sport Sack to give your dog about a 3" boost 3" (7.62 cm)to make their ride more comfy.”