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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 133 reviews
Game changer

That block is definitely a game changer. I have a 10 pound chihuahua and the XS sack seemed too big until I placed the block.
The block is also well made..

Coz Bruer
K9 Booster Block

Absolutely perfect! My little man is able to sit up correctly


Bailey can see where we are walking!

Very durable!

Very durable, loved can remove cover to wash and made it sturdy for my shih tzu to sit upright.

Love it!

My sister told me about your backpack. She gave me great reviews. She does bike events and has one for her dog because she takes her dog to all of her events. I bought one and don’t regret it! Love it and my baby girl loves it too! Sturdy material, durable straps and I have no fear my baby will fall out. I thought it was expensive but when I saw the product with my own eyes it was well worth the money! Excellent job on making it! I plan on getting the booster next to help elevate her but she did great. I knew she felt safe and secure as she didn’t show any signs off struggle. We both love it.