The 3SB3100-8AC21 from Siemens is a 3SB3 series, non-illuminated, single pole Twist Actuator, which is a type of switch or button. It has a robust stainless steel housing and a synthetic actuator head, making it vandal and dust-proof. The large diameter and tactile feedback, paired with the bright yellow contrast color, results in an intuitive operation. It is designed for use in harsh environments and is rated with an IP67 protection rating. It is suitable for flush, surface, or snap-in mounting. The contacts are rated for a maximum current of 1A at 30 VDC. It can also be used as a signaling contacts. This part is suitable for use in industrial systems as well as for home automation applications.