Use BLOTTO whenever procedures call for immunoanalytical grade non-fat dry milk. Alternative blocking agents such as BLOTTO A (solution of TBS, 5% non-fat dry milk and 0.05% Tween-20) and BLOTTO B (solution of TBS, 1% non-fat dry milk, 1% BSA and 0.05% Tween-20) are also available. BLOTTO A is a convenient general purpose blocking agent. BLOTTO B is recommended for blocking when phospho specific antibodies are used. BLOTTO A and BLOTTO B provide Tween-20 in a separate vial in liquid form. Users should consider the addition of Tween-20, protease inhibitors and phosphatase inhibitors when required. Typically 50 mM NaF can be added to BLOTTO solutions to inhibit phosphatase activity. We recommend using 1X working solutions of BLOTTO A or BLOTTO B directly for blocking purposes and primary antibody dilution and incubation.