Bongwoori is a genetically encoded fluorescent voltage indicator. It consists of the voltage-sensing domain from the Ciona intestinalis VSP gene (GB:AB183035), that has been mutated to carry three amino acid substitutions (A154D in the S2 transmembrane region, R217Q and R229I in the S4 transmembrane region), fused via a peptide linker to super ecliptic pHluorin containing the amino acid replacement A227D (PMID:25568129). For detailed kinetic and spectral properties, see PMID:25568129.