Twin needles are designed for practical and decorative sewing such as pin tucking, seam finishes, top stitching etc. Metafil needles are for embroidery with metallic threads. Use at reduced speed 

Size - 80/12
Stitch gap - 2.00mm
Use - For metallic or rayon embroidery threads preventing stripping features large eye for easy threading. 
Machines - Suits all modern machines; Bernina,Bernette, Brother, Elna, Husqvarna, Janome, New Home, Pfaff, Simplicity, Singer, Toyota, Viking ect.
Type - Pre-packaged, 1 needle in a pack