EC Buying 5Pcs 3-5V Optocoupler Isolation Board Optoelectronic Isolator EL817 PC817 Card Rail Bracket Input 3-5 V Optocoupler Isolation Module 1 Channel Opto PNP NPN Signal Converter

EC Buying 5Pcs 3-5V Optocoupler Isolation Board Optoelectronic Isolator EL817 PC817 Card Rail Bracket Input 3-5 V Optocoupler Isolation Module 1 Channel Opto PNP NPN Signal Converter

HiLetgo 2pcs 5V One Channel Relay Module Relay Switch with OPTO Isolation High Low Level Trigger

Twidec/6Pcs Micro Limit Switch Short Straight Hinge Lever Arm SPDT Snap Action Switch for Arduino V-152-1C25