- To mount filters and other attachments with a diameter of 37 mm to lenses with a diameter of 30 mm ,- Adapter for all lenses and attachments with screw thread ,- Precision metal rings with matt black surface - Adapter Thread: 37 mm ,- Adapter Thread Type: Screwed Socket ,- Camera/Lens Thread: 30 mm ,- Camera/Lens Thread Type: Screwed Socket ,- Colour: Black 2 years legal warranty only