3400-OS Oral Surgery MXR-Flowmeter with Porter Scavenger Breathing Circuit includes: 3000-OS MXR Flowmeter (includes P2407A oral surgery threaded bag tee w/adapter) 4100 Three Liter Bag 5155-1 Porter Adult Inhaler Scavenger Assembly, complete Special Features: Higher Maximum flow rates Oral Surgery bag tee for 221OK Y valve