The Sprecher and Schuh 4 pole relays are unique for both their reliability and compact size. Each relay comes with a standard 4 poles and additional auxiliary contacts can be added for up to 12 total poles (4 top mounted and 2 side mounted for each side). These relays use the same auxiliary contact blocks as the CA7 contactors and are easily installed without tools. CS7 control relays are perfect for fail-safe control circuits. An interlock contact design, which maintains minimum 0.3mm clearance, prevents the NC contact from reclosing if the NO contact is welded when in operation. This feature not only includes the base contact poles, but extends to the front and/or side mounted auxiliary contacts. This is a requirement in safety circuits and is backed by SUVA-PRO certification.