Avon Rider and Bath Rider tickets are usable on Abus and First Bus. They can be purchased from either bus company.
However, First Bus also have their own 'rider' ticket, which is only usable on First buses.
Please ensure to specify you require an Avon Rider or Bath Rider when purchasing a ticket if you wish to use both Abus and Frist buses. If you purchase the First Bus 'rider', Abus cannot accept it.