Listing is for a 4560 OI O.I. Analytical OI O.I. Analytical 307124 Regulator In Carrier Gas FC Tube Assembly for 1 5/8" Diameter. NEW! Please check compatibility with your application prior to bidding. Immediate payment is appreciated. Item(s) will be re-listed after 2 days if payment has not been received. Free shipping to the US! Thank you.