Selector Control is a control resin for all Selector resins available from NanoTag Biotechnologies, which are based on 4 % cross-linked agarose beads. It was prepared using the same activation and quenching chemistry that was used for preparation of Selector resins, but is not charged with any single-domain antibody. Selector Control is thus the ideal resin for pre-depletion of extracts or as a side-by-side specificity control for any of NanoTag's Selector resins. When using as a specificity control, Selector Control and the corresponding sdAb-charged Selector Resin should be used under identical experimental conditions. For an overview about recommended procedures visit our webpage at www.nano-tag.com/protocols.