This is a straight adapter with a black nickel finish, converting from 1/8 inch external thread to 1/4 inch internal thread, specifically designed for the outlet of an Eheim pump 1046.

Before screwing in the adapter, the sealing ring should be coated with a lubricant, as it may otherwise be pulled out of its groove and exert excessive pressure on the plastic ring of the pump in the upper area. Alternatively, it is also sufficient to screw in the adapter only partially, stopping at the rubber itself.