MADE TO TAKE A BEATING: Each one has a water-weighted bottom (filled on site) that makes it pop right back up for continuous fun. PATCHES INCLUDED: Includes patch kit in case of accidental puncture. INSTRUCTIONS: The Inflatable Knockdown Targets have two compartments. The base needs to be filled with water BEFORE the top is filled with air. Be careful not to over-inflate and avoid striking the target with any sharp objects. PROFESSIONALLY MADE: All our products are designed by Tennis pros with years of experience and expertise. ONCOURT OFFCOURT: We are the leading creative resource for youth tennis, training aids, court equipment and ball machines. Over 10 million players have improved using our products in over 100 countries.