Great for practicing 2-shot combinations such as a volley followed by a lob or topspin followed by backspin. Shot Delay feature allows the player time to return to the baseline after going to the net  at the end of a drill.2 distinct programmable shots, 1-shot delay, variable topspin and backspin, 7-position programmable electronic direction with programmable random, variable electronic height. 2-function remote (on/off with drill reset). Upgradeable and inter-changeable (accepts all controllers). Can be used with Serve Lift. Holds 300 balls.