MagicMark XP Western Protein Standard provides direct marker band visualization on Western blots. Each protein contains an IgG binding site, allowing marker visualization using the same antibody-conjugate reagents and protocol for the target protein as a user’s immunoassay. The standard offers a molecular weight range of 20 to 220 kDa and allows molecular weight estimation of a target protein directly on Western blots. Invitrogen Corp. 800-955-6288 www.invitrogen.com