Our CELT-331 product is a potent and selective hCB2 fluorescent ligand that shows a high affinity for hCB2 receptors and selectivity over hCB1. It has a Ki value of 75.9 nM for hCB2 receptors in radioligand binding assay. CELT-331 is suitable for HTRF binding assays as a valid alternative to radioligand binding assays. It is available in a 10ug vial that allows for the preparation of 150ml of 100nM working solution to test CB2R. CELT-331 is designed to allow for cell visualization in fluorescence microscopy, confocal, and high-content system experiments and is potentially suitable for other fluorescence-based assays.