This is my partner's manufactry.Our production line for Oxygen Cylinder can supply Oxygen Cyliner with OD from 159mm to 325mm with volume from 20L to 90L, standard to be GB-5099 or ISO 9809; you accept min order quantity 1200PCS per shipment, our payment term is 30% TT advance + 70% L/C at sight or 70% TT against SGS/IEI inspection; if you are interested in our products, please contact with us, baigongcylider at xxxxxBest regardsYours, Andy