High purity tris(azide-PEG10-NHCO-ethoxyethyl)amine from Axispharm is a branched PEG linker with three terminal azide groups. Azido groups can be PEGylated by Click Chemistry.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.