Can I use this with a diono rainier?

Hi C Charlton, thank you for your enquiry, the Britax Car Seat Travel Cart is suitable for most Car Seat Brands however, we would suggest contacting your local Baby On The Move Store in regards to this fittin the Diono Rainier. We hope this helps. ?For further information on this or any of our other products available, if you follow the link https://www.babyonthemove.co.nz/store-locations/ this will take you to our online store finder. Here you can find contact details for your nearest Baby On The Move Store where one of our team experts will be happy to assist you in your product search and help answer any further questions you may have. We hope this has helped with your query.