SUKRAGRAHA LM393 Chip Motor Measuring Comparator Speed Sensor Module Slot Type IR Optocoupler for MCU Arduino Go to amazon.com Related posts Expert choice for lm393 module arduino Featurewidely be used in dynamo speed detecting or for Arduino DIY projectMain Chip : LM393Working Voltage : DC 3.3-12VSlotted Width : 5mm/ 0.2";Hole Size : 3mm/ 0.12"PCB Board Size : 33 x 14mm/ 1.3" x 0.55" (L*W)