this auction is for three  ohmeda vents model 7850, they are in untested condition and  seem complete except for the knobs , any 1/8 allen set screw knobs can be used though ,ask any and all questions prior to bidding , i will cancel bids from excessive neg feedbackers , i will take greedpal and business and personal checks as well as USPS MONEY ORDERS ONLY, no other tyope of money orders will be accepted, [received a phony 2 weeks ago]buyer pays actual shipping  what they charge, is what you pay again ask all questions first , sorry only usa bidders  hawaii too,aloha