The Zip Throw Tandem Units have an adjustable ball height allowing athletes to work on catching, passing, blocking and shooting at any height. Drills have been designed for drivers, goalies, and centers to address and isolate nearly every technical movement. Athletes can practice unlimited reps without the ball ever hitting the water. Having several Zip Throw stations is ideal for a coach who needs to work on specific skills or leg conditioning for more than one or two athletes at time. The Zip Throw Tandem Unit is a popular option for clubs and teams that seek to set up multiple stations. The posts are fitted for stanchions that are found on most collegiate, high school, and club pool decks. The diameter of the stanchion hole is typically 1.9 inches.