SIL rating indicates how much the system is designed to reduce risk of failure. SIL ratings are referred to as SIL 1, 2, 3, and 4. With a SIL rating, no single component is intrinsically “SIL rated”; instead, the system as a whole is given a SIL rating. SIL rated components help achieve SIL system rating with greater ease. To contextualize this, a designer may want to design a SIL 3 system. In order to achieve a SIL 3 system, the risk reduction factor needs to be 1 in 10,000. There are many ways to achieve this, but by using a SIL rated product the designer can achieve this faster and more efficiently. PL is the safety performance level rating of a control system. Like SIL, it indicates how much a system reduces risk but is more general. While SIL refers to machinery specific electrically controlled systems, PL refers to any control system. Also like SIL, PL is a system wide rating. Having a PL rated part does not rate the system for a certain PL level, but helps the designer achieve PL system wide rating. PL ratings are referred to as PL c, b, d, and e.