Our CELT-252 ligand is a highly potent fluorescent antagonist developed for hA1R  testing with a Ki of 39 nM in radioligand binding assay. The product comes in a 10ug vial that enables the preparation of 69ml of 100nM working solution to test AT1R. Our fluorescent antagonist is ideal for visualization in confocal microscopy and high-content system experiments. Our CELT-252 ligand is potentially suitable for other fluorescence-based assays such as Fluorescence Polarization.