Omron Safety (Sti) D4SL-N3NFA-DProduct Attribute Attribute Value Actuator Type Solenoid Locked Key Contact Form 2 NC, 1 NO + 2 NC, 1 NO Series D4SL Series Overview D4SL Safety Guard lock Door Switch The D4SL N series from Omron is a small Class 6 contact Guard Lock Switch. The significantly reduced solenoid current of the D4SL N contributes to reduced power supply costs. The safety door switch also conforms to the following EC Directives: Machinery Directive, Low Voltage Directive,