Discrete poly-(ethylene glycol) or Discrete PEG. Like traditional PEGs, our products contain a hydrophilic, water-soluble backbone consisting of repeating ethylene oxide units; however unlike traditional PEGs each of our products represents a single compound with a unique, specific, single molecular weight (MW). Our dPEG® products are synthesized from pure building blocks (e.g. triethylene glycol or tetraethylene glycol) in a series of step-wise reactions to provide specific MWs, architectures, functional groups, and organic moieties suited for a wide variety of applications. These products have now been used for the modification of therapeutic macromolecules, as linkers in antibody-drug conjugates (ADCs), for bioconjugation of biologics, for surface modification, and in diagnostics, to name a few.