m-PEG8-Br(CAT: I016384) is a monodisperse polyethylene glycol (PEG) linker consisting of eight ethylene glycol units terminated with a reactive bromide group. The PEG8 spacer imparts excellent hydrophilicity, flexibility, and reduced steric hindrance, which improves solubility and biocompatibility in chemical and biological systems. The terminal bromide functions as an electrophilic site, enabling nucleophilic substitution reactions with amines, thiols, or other nucleophiles to introduce diverse functionalities. This reagent is widely applied in drug discovery, polymer modification, and bioconjugation, particularly for introducing PEGylated chains onto biomolecules, surfaces, or small molecules to enhance stability, solubility, and pharmacokinetic properties.