25 Pcs Optocoupler, PC817C Optocoupler 4 Pin Mounting Optocoupler 2.5mm Pitch Coupler, Optocoupler PC817C, Optocoupler DIP-4 PC817C, High Density Mounting Type Optocoupler IC. ✎ Model: PC817C. ⍟Purpose: The purpose of the photocoupler is to increase safety, reduce circuit noise and simplify the circuit design.
eBay