Determining dog size for the K9 Sport Sack is not a science. If your dog is in between sizes, has a wide frame but a short length, or is still growing - the Booster Block Backpack Pad fits comfortably in the bottom of your K9 Sport Sack and increases your dog's position by 7.62 cm. At the same time, it helps you and your dog to be more comfortable when using the K9 Sport Sack.

• made of solid and high-quality foam
• removable, washable fabric cover
• using two blocks for a 6-inch lift