The ChromoTek Halo-Trap Magnetic Agarose consists of an anti-Halo-tag Nanobody (VHH), which is covalently bound to magnetic agarose beads. Halo-Trap Magnetic Agarose is used to immunoprecipitate Halo-tag proteins from cell extracts of various organisms like mammals, plants, bacteria, yeast, insects etc. in the presence or absence of a covalently bound ligand. The interaction between Halo-Trap and the Halo-tag protein is reversible.