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K9 Booster Block


Sizing your dog for a K9 Sport Sack® isn't an exact science. If your dog is in between sizes, has a wide body but short in length, or is still growing, the Booster Block fits snuggly in the bottom of your K9 Sport Sack to boost your dog up 3" (7.62 cm). It helps make the K9 Sport Sack experience more comfortable for you and your dog.

  • Constructed of sturdy, quality foam
  • Removable, washable cloth cover
  • Use two blocks for a 6" lift
  • XS/S measures 3" tall * 8" wide * 5" deep (7.62 cm * 20.32 cm * 12.7 cm)
  • XS/S are interchangeable between XS and S sized backpacks
  • M/L measures 3" tall * 10" wide * 6" deep (7.62 cm * 25.4 cm * 15.24 cm)
  • M/L are interchangeable between M and L sized backpacks and are also compatible with XL and XXL if necessary

Customer Reviews

Based on 127 reviews
Melissa Reece
Awesome and comfortable!

The sportsack is great for me to ride my bike with my 16 Lb. dog. The booster block greatly improved the fit for him and me because his feet had something solid to rest on and his head stayed high, paws on my shoulders.

He wasn't too sure at first, trying to get him properly in the sack. But after practicing a few times, he realized the sack meant he would get to stay with me and go somewhere at the same time. He loves it now, gets excited but quickly sits still so I can "bag him up".
Thank you for making K9Sportsack with booster block a comfortable and well designed product. Definitely worth the money.
Melissa Reece

Michael A
Excellent backpack!

My Frenchie enjoys the sitting in the K9 Sport Sack!

Chris Villalobos
Pepper Approves

We got the foam block to let our puppy enjoy the larger bag for our other dogs, let’s just say she now looks down upon the other dogs and we will have to figure out how to get her to walk once she gets all her shots.

Happy Little Bugger

Really love the K9 sportsack, but the booster kicked it up a whole other level. Now this tiny guy can peak up and around like the big boys.

Jennifer Charvet
Block made all the difference

My Shih Tzu loves his back pack now that he is properly sized with the foam block insert.