These are no green oring and that's a good thing cos these are the best material for a high friction and temperature environment which means they are perfect for airsoft and gel blaster replicas they are a extremely low friction material which intern cause the fps and consistency to be better in a high speed aeg build or even a standard aeg build and the friction will reduce the overall temperature in your cylinders and the extreme chemical resistant means that you don't have to worry about what grease may get into your cylinder under normal operation they are a lifetime seal I would say as I have been running them for over a year with absolutely 0 loss of seal with them
