Our CELT-095 ligand is a highly potent fluorescent antagonist developed for M₁R and M₂R testing with a K_i of 57.77 nM and 37.7 nM, respectively in radioligand binding assay. The product comes in a 10 μg vial that enables the preparation of 73 mL of 100 nM working solution to test M₁R/M₂R. Our fluorescent antagonist is ideal for visualization in confocal microscopy and high-content system experiments. Our CELT-095 ligand is potentially suitable for other fluorescence-based assays.