This site has limited support for your browser. We recommend switching to Edge, Chrome, Safari, or Firefox.

Kolossus | Big Dog Carrier & Backpacking Pack


Completely redesigned in appearance, construction, and functionality, the Kolossus, formerly known as the Rover 2, is THE big dog backpack carrier that now doubles as a backpacking pack. It is ideal for carrying medium to large dogs and available in sizes L-XXL. Kolossus technology is top of the line in pet/human safety and comfort. Adjustable shoulder/torso sizing makes this backpack more suitable than ever for all body types (as long as you can withstand the weight). When you’re not carrying your 4-legged friend, the backpack easily converts to carry your gear with up to 60 liters of space. Use this backpack for strenuous hikes, bike rides, and public transit.

For Dogs Ranging 20-80 lbs (9-36 kgs)
50-60 liter capacity

Kolossus sizing length from the collar to the base of the tail: L 20-23 inches, XL 23-26 inches, XXL 26-29 inches

View More Sizing Instruction

  • Backpacking Pack Conversion
  • Adjustable Shoulder/Torso Height
  • Removable Lap Belt with Hip Pockets & Waste Bag Dispenser
  • Internal Frame with Inner Padding for Dog Comfort
  • Padded Back Panel with Increased Airflow
  • Removable Storage/Dog Back Support Pack with Hydro Port
  • Weight Distribution Straps
  • Side Cooling Venting Zippers
  • Wide Base to accommodate your pet and its tail
  • Detachable Dog Sun/Rain Hood
  • Dog Lumbar Support Straps
  • 300D Ripstop Oxford Polyester Material
  • Matching Hook & Loop Strip for Custom Patch

Compare K9 Sport Sack Carriers

Rover 2  Comparison

View Patent Info


All K9 Sport Sack carriers are specially developed under the close direction of animal professionals, veterinarians, dog trainers, and outdoor product engineers to be ergonomic, safe, and strong.

Customer Reviews

Based on 75 reviews
Lindsay Gregory
Great for hefty boys

My senior puppy has reached the point of no longer being able to hike with us, but still wants to go. This makes it easier. Getting him in was simple enough (he's also super chill and lets me do whatever with him). He does weigh Bout 85 pounds, so carrying him is a little hefty, but we're working on it. It does help to have a second person to hold him and the bag upright while I get it adjusted in my shoulders sitting down before standing with him.

Motorcycle Dog

My dog had absolutely loved this bag. we get to go on motorcycle rides together and she loves it. Great quality and fits her comfortably

Tina Vallecillo
New Hampshire hike

Went to the white mountains in NH. I knew the hike would be a little ruff after a while my puppy had enough thankfully we had this bag.Best investment when hiking hard terrain. If it wasn't for this bag I wouldn't have known what to do. So glad I bought this last minute. Using the block at the bottom made it comfortable for my 5 month old Australian shepherd. It made it possible to do hard rock scrambles. You need to practice with your dog before hand to get them comfortable and if you are short this bag will be hard. When trying up or down large jumps the bag might bottom out.

Changed our lives

This backpack has changed our lives. Thanks to it, we can finally spend our vacations and free time together - all three of us, without leaving our four-legged daughter at home alone.
Our 8-year-old Lia gets tired rather quickly, she is not fond of long treks, she much prefers swimming and running after a ball. Each of our previous vacations consisted of short walks and throwing the ball in parks. Thanks to the purchase of this backpack, Lia can share our passions - mountain hiking. She's comfortable there, she watches the surrounding landscapes with curiosity, and most importantly - as soon as she sees us getting ready to put her in, she gets very excited and even adopts a special pose to make it easier to put her in there! K9 sport sack is the best purchase of our lives! The only remark - it is too big for our mutt (dachshund/terrier mix, weight 14kg). We chose the size L, and despite putting a booster block, we need an extra cushion to make Lia comfortable. For next season we will definitely buy a smaller model. Greetings from Poland!

Justin Spence
Awesome pack!

You guys thought of everything!!