sand weighted  with durable vinyl cover

air may be added to change size and firmness of the ball (note:  These balls are shipped in the form that they are intended to be used.  Some individuals may want to add more air, although it is not necessary.  If you are looking for bouncy, hard  medicine balls, these are not for you.)

use a sport ball needle for adding air (not included) - some sand may escape the ball when inserting a sport ball needle - the ball is not defective and air will inflate the ball making the ball harder

please note:  these medicine balls do not bounce

warranty:  manufacturer's discretion