Ace2N-2AA-mNeon2 is a negative polarity fluorescent voltage sensor (shows a decrease in fluorescence during voltage depolarization events). It consists of a voltage-sensitive rhodopsin sequence fused via a linker to the fluorescent mNeonGreen protein. Ace2N-2AA-mNeon2 was generated by mutagenesis of Ace2N-2AA-mNeon, containing in addition the mutations N81S and G229Y, and has improved fluorescence response to depolarizing voltages compared to Ace2N-2AA-mNeon (PMID:36378956). For detailed kinetic and spectral properties and a comparison of Ace2N-2AA-mNeon2 with other fluorescent voltage indicators, see PMID:36378956.