The QSHE-open is a static electrochemical cuvette for the QCM-I systems. It fits the thermal controlled internal QCM-I chambers and the QMH-ext. external sensor holders. It has an open 5ml solution volume chamber made from PEEK and comes with an Ag/AgCl reference and a Pt wire counter electrode. The sealing is made with VITON O rings. The lid also has fittings for gas in- and out-lets, or to allow for real-time sample additions.