When Closing the Ball Container Pressure Jar Lid, Screw the Bottle Body to the Pressure Value of 14Psi and Leave the Tennis Shape Restore Jar for a While. the Pressure of the Tennis Ball Will Restore Bouncing and Will Be the Same Fresh As That of the Ball. Keep Tennis Balls Bounce and Elastic, That is a One of a Kind Tennis Ball Storage System That Holds Balls Under Equal Internal and External Pressures Preventing Air from Seeping in and out of Pores. Air Inside Will Not Affect the Integrity of the Tennis Ball Storage Restore Pressure . Can Storage 3 Tennis Balls According to Pressure, Stretch for All Kinds of Matching. Use for Tennis Protection, Ball Pressure Canister, Pressurized Tennis Ball, Sports Ball Repair, Tennis Ball Container Pressure, Sports Tennis Pressure Repair, Tennis Shape Restore and Outdoor Exercise Sport Supplies. Storage Bottle Box Made of High Quality Fibre-reinforced Plastic Material, Endurance, Sturdy and Durable in Use for Tennis Ball Protector Compressor, Paddle Ball Decompressor, Ball Pressurizer, Ball Pressure Canister, Pressure Jar Storage Box, Tennis Ball Container, Tennis Shape Restore, Pressure Maintaining Repairing Container, Etc. Product Use: Restore tennis shape, Keep Tennis Balls Bouncing, Ball Pressurizer, Tennis Ball Protector Compressor, Paddle Ball Decompressor, Tennis Ball Pressure Repairing, Pressurized Tennis Ball Tank, Tennis Ball Pressure Canister. Colour:Blue+Black Material:ABS Size:Approx. 21.5 x 8.5 x 8.5cm Package Contents: 2x Tennis Ball Pressure Maintain Repair Container Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.