This top only fits Threadless stems, NOT internally threaded stems or push-fit stems in bioplastic! It has no threads at all, so it cannot be screwed into any other piece of jewelry.
Titan Blackline® is black jewelry in Titanium, not "dyed" black in the classic sense, the black color is created through an electrolytic anodizing process, not by applying an additional coating layer, such as PVD coating. This means that the black appearance does not come from a separate metal or material coating, but from a treatment of the titanium surface itself.
Blackline® is glossy black and a delight to the eye, they are incredibly beautiful as they are but also really cool if you combine with other colors.