The Discovery-4 automated peptide synthesizer is capable of preparing four peptides at the same time. It can produce peptides from 0.05 to 3.0 mmoles per reactor, and each reactor can run independently following a different scale and protocol. Each reaction vessel has a dedicated preactivation vessel, which allows the synthesis of peptides with a single coupling protocol. Sequences can be added and removed without interrupting the instrument’s operation. The Discovery-4 utilizes common coupling reagents such as HBTU, HATU, PyBOP, DIC/HOBt, and bulk AA solutions with concentrations up to 0.5 mmol.