Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41.
N 4858 (OTTO) Niobium slug, 6.35mm (0.25in) dia x 12.7mm (0.50in) length, 99.95% Cas 7440-03-1 - used in high temperature and super alloys of Zn and Ti.