Application: The chain breaker is used to adjust the length of a roller chain. Fitment: This chain breaker can be applied to roller chain from 420 to 530, 420 428 520 525 528 530. It covers most main roller chain type. Materal: The chain breaker is forged with high quality molybdenum steel. It has a much higher strenght than nomal steel type to prevent any demange during usage. Design: The chain breaker has a ergonomics design which will make your work easy and confortable. Warranty: 100% satisfaction. If you come across any issues during usage. We are here to help. Application: The chain breaker is fit for 420 428 520 525 528 530 roller chain. Package: The package come with one piece chain breaker