Thallium indicator, membrane permeable. Thallos is a green fluorescent, intracellular thallium (Tl⁺) indicator, and has been the standard for fluorescence-based potassium (K⁺) channel HTS for nearly 2 decades. Thallos also delivers outstanding results for a wide variety of monovalent cation (sodium – Na⁺) channels, transporters, and GPCRs. Offers outstanding cell loading and excellent compatibility with commonly available FITC filters. Excitation: 490 nm | Emission: 515 nm