balls are not all balls. They don't inflate themselves to the same or weight. Looks like the color on the ball has a lot to do with it. The rainbow ball is harder and smaller. But they are for kids and for play - so it doesn't matter. I tried using them on a 4-7 year old kickball team and couldn't use 4 of them because they were too different.
Bedwina Knobby Assorted Sensory Colors
9 Review
6-Pack Baby & Toddler Activity Rattle Balls - Clear Plastic Durable Ball Ramp Toy Replacement Balls.
14 Review
Sensory Baby Ball By Edushape - 7 Inch Transparent Primary Color Ball For Enhanced Gross Motor Skills Development In Infants 6 Months & Up - Vibrant Colorful & Textured Ball For Babies - Single Pack
36 Review
π GoSports Official Kickball Pump Pack: Ultimate Inflation Solution for Your Game!
9 Review
GOGOSO Pink Balls For Ball Pit - Pack Of 100 Ball Pits Ball Pink, BPA Free Plastic Ball Toys Crush Proof Ocean Balls Phthalate Free For Girls Toddlers Indoor Outdoor - Pearl Pink Colors
10 Review
Fun And Safe Playtime With PlayMaty 100 Colorful Pit Balls For Kids
30 Review
Get Ready To Rule With Playkidz My First Princess Makeup Chest β The Ultimate Deluxe Cosmetic And Real Makeup Palette For Girls With Washable Features And An In-Built Mirror
16 Review
Revolutionize Playtime with π Click Play Phthalate Crush Plastic
9 Review