You should use caution when buying a cylinder on the Internet. All cylinders above 80cf are traditionally rented or leased. They will have a name embossed on the neck ring. This means they are owned by the company with name on neck ring. Cylinders under 80cf are usually called customer owned or exchange cylinders. Large cylinders require an affidavit or proof of ownership. Many welding suppliers, in an effort to stop internet sales now ask for this on the 80cf and smaller cylinders, but it is not required by law. We strongly suggest you check with your gas supplier before buying cylinders to see what they will or will not fill or exchange. Also many large suppliers really do not want small accounts, and may have several requirements in place to try and keep you away. All high pressure cylinders as for, helium, nitrogen, argon and argon mixes that we sell have 10 year hydro-test stamp, with + for 10% overfill. All will have recent hydro-test date and are new cylinders. All acetylene cylinders will have date made stamped into them, and will require inspection within 10 years. Carbon dioxide cylinders, steel or aluminum require hydro-test every 5 years, as do some other gases. If you exchange cylinders with your supplier, he usually accepts all re-test or re-qualification charges. If you have the cylinder you purchase filled and keep it each time, you will incur these expenses in time. Cylinders only require a lable after being filled the first time, new cylinders that have never been filled do not require a lable by D.O.T. , which writes and oversees all cylinder regulations and the filling of cylinders. There should be no charges for first time exchange except the gas. If there are, then I suggest shopping elsewhere for gas.
Oxygen cylinders should always have a CGA-540 valve, Inert gases, helium, nitrogen, argon and argon mixes should have a CGA-580 valve. Acetylene will have one of 4 valves, 75cf and up either CGA-300 or CGA-510, MC cylinder will be CGA-200, B cylinder CGA-520. While there are adaptors available to change your regulator to a different cylinder valve or gas service, we strongly suggest you have your gas supplier change the nut and nipple on regulator and verify the regulator is safe in application to be used.
Link below to Cylinders we offer on EBay.