Material: Stainless Steel.;Color:Black,Gold,Silver,Blue,Multicolor, 1 pair for each color;Its special design will make you look unique.;It is a good gift for your lover,family,friend and coworkers;pin diameter : 1mm/0.039(approx.); about 9x10mm/0.35*0.39 for the inside circle, 13mmx13mm/0.51*0.51 for the outside circle