You are setting up the treatment area for a patient who will be receiving a Class II composite resin on tooth #5. Your tray setup includes a high-speed handpiece, low-speed motor, contra-angle attachment, #169 friction grip bur, #4 round latch-type bur,mandrel, sandpaper discs, and rubber points.
1.Which hose on the dental unit do you attach to the high-speed handpiece?