Used as a cross-linking agent in biochemistry and molecular biology to covalently link proteins, peptides, or other biomolecules. Its primary application is in the preparation of antibody-drug conjugates (ADCs) and protein-protein conjugates, where it enables controlled linkage through sulfhydryl and amine groups. The reagent contains an NHS ester at each end and a disulfide bond in the spacer arm, making the cross-link cleavable under reducing conditions. This feature is valuable in drug delivery systems, allowing release of active components inside cells. It is also employed in immobilizing biomolecules onto surfaces for biosensors, ELISA, and affinity chromatography. The hydrolytic stability and moderate reaction kinetics make it suitable for conjugation under mild aqueous conditions.