Azido-PEG10-CH2CO2-NHS is a PROTAC linker of the PEG class, utilized for synthesizing PROTAC molecules. It serves as a click chemistry reagent, featuring an Azide group that participates in copper-catalyzed azide-alkyne cycloaddition reactions (CuAAc) with alkyne-containing molecules. Additionally, it can engage in strain-promoted azide-alkyne cycloaddition reactions (SPAAC) with molecules that have DBCO or BCN groups.