Good question, thanks for asking. Unfortunately, the MMBCC-DRAIN-01 will not fit the MMOCC-RB, as this kit was designed for the MMBCC-UNI. Additionally, we do not currently offer a petcock drain kit for the MMOCC-RB. We apologize for the inconvenience. However, the MMOCC-RB comes with a magnetic drain plug included in the kit.
Please feel free to reach out to us at firstname.lastname@example.org, and we would be happy to assist further.