Mal-amido-PEG10-C2-NHSester is a noncleavable antibody-drug conjugate (ADC) linker that consists of a maleimide group and an N-hydroxysuccinimide (NHS) ester. The NHSester enables efficient labeling of primary amines (-NH2) in proteins, amine-modified oligonucleotides, and other amine-containing molecules[1][2].