Analog Set Multi-function, Ultra-Slim17.5 mm Timers for Track Mounting Wide AC/DC power supply range (24 to 230 VAC/24 to 48 VDC) minimizes inventory Smart Dial/Selector-Locking Mechanism prevents the dials and selectors on the timers front panel from being operated without authorization (lock can only be unlocked and locked with an optional pen-type Lock Key) Eight operating modes (H3DS-M) and four operating modes (H3DS-S) to cover a wide range of applications Offers wide time setting range of 0.10 s to 120 h Finger protection terminal block prevents shock High immunity to inverter noise