This AOPEN Open Book 1735 Replacement Battery Pack is 100% compatable with the BTP-33A1 AOPEN Open Book 1735 Replacement Battery Pack. Our batteries and accessories are made with high quality parts and are guaranteed to meet or exceed the original equipment manufacturers specifications at a reduced price. All batteries are tested for 100% quality control assurance. This AOPEN Open Book 1735 Replacement Battery Pack includes a warranty to guarantee that it has no manufacturing defects.