This IBM ThinkPad 350, 350C RTC Battery is 100% compatable with the CL2020-PS1 IBM ThinkPad 350, 350C RTC Battery. 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 IBM ThinkPad 350, 350C RTC Battery includes a warranty to guarantee that it has no manufacturing defects.