Advanced BioChemicals (ABC) offer 4-Arm PEG-SS with MW 2kDa, MW 5kDa, MW 10kDa, MW 20kDa and MW 40kDa, in 1g, 5g and 10g packing sizes. Different MW of 4-Arm PEG-SS products may be available by custom synthesis, please email us at tech@advancedbiochemicals.com for details. Advanced BioChemicals (ABC) also provide repackaging services, please contact us at sales@advancedbiochemicals.com for a free quote.