Biotin is a hapten widely used to label biomolecules due to its high affinity for avidin/streptavidin systems. The anti-biotin antibody allows sensitive detection of biotinylated molecules as a second-step reagent. Its conjugation with PE provides an intense signal, making it particularly suitable for flow cytometry, immunophenotyping, multicolor panels, and the detection of low-abundance targets using indirect labeling strategies.