6-CR6G, SE [6-Carboxyrhodamine 6G, succinimidyl ester] *Single isomer*

6-CR6G, SE is amine-reactive derivative of 6-CR6G. It is preferred for some complicated biological applications where reproducibility is more critical than material cost since the minor positional difference between 5-CR6G and 6-CR6G might significantly affect some biological properties of the underlying conjugates.