The Bison Sand Volleyball Ground Sleeve is designed to be used with Bison outdoor volleyball systems (see skus A25-902 and A25-903). This sleeve allows for easy removal of volleyball net posts when they are not in use. Sold by the each, this steel sleeve features a durable molded plastic cap that keeps sand out. When installed according to instructions (download instructions under 'additional info' tab), the top of the sleeve is approximately 6″ below the top of the sand, so sand can be used for other activities.