17 P/N:8023488. Original positionPress the button, the chair and backrest will move to the original positionautomatically(Original position : backrest highest , the chair lowest) andlight off . Press this button again , the chair returns to former position andlight on. The chair shall stop at a new position by halfway stop.. Spitting buttonPress the button, the chair and backrest will move to spitting positionautomatically(Spitting position : backrest highest , the chair is still) andlight off . Press this button again , the chair returns to former position andlight on. The chair shall stop at a new position by halfway stop.05.6 Foot controlDelivery systems are equipped with wet-dry,variable speed, disc type footcontrols. Foot pressure on any part of the control disc controls the flow ofair to the active handpiece.Figure 10Water Coolant On/Off:This toggle interrupts the flow of water coolant to the handpieces whenperforming a procedure that requires dry cutting.User's Manual of Beyond 300/301 Delivery System