This is a single replacement silicone o-ring for the Enolmatic/Enolmaster filter cartridges that help create a seal on these cartridges. While these cartridge filters (both plastic and stainless steel) come with two on the ends of the cartridge, you might lose one of these o-rings, or find yourself in the position where the o-rings wear out before the filter cartridge! If this is the case, these are the replacement o-rings you need!
Genuine replacement part from TENCO.