iUniker Raspberry Pi Power Switch, Raspberry Pi 3 Power Supply Cord Pi Power Switch Cable Switch Push On Off for Raspberry Pi 3,Pi 2,B+,Zero w MicroUSB Female to Male (4-Pack)

These items don't pass data lines through, plus they produce low voltage issues.Not useful. Beware!

I was happy when these arrived , was going to use with my raspberry pi 3b+ . Low power bolt warning shows on my pi when I use this. Wish I read the other reviews first

UPDATE: 01/31/2019==================When I actually bought this - blindly assumed that this'll support Data passthrough for my ESP8266 & ESP32 micro controllers - which it didn't. But since it was my fault that I didn't read other comments before ordered it - I decided to keep it for my Raspberry Pis.Today had to chance to test it on both Raspberry Pi 2 & 3 - with a 5v 3.4A power supply. Both complains about voltage drop. I bought a 4 Pack and all of them having the same issue. Hence decided to return this back to where it belongs.ORIGINAL:==========Beware before you buy this. Garbage!!!

I tried these on a 2 and a 3 B+. Both were attached to an external drive, Ethernet, a USB mouse, and HDMI. Without the switch in place, both ran fine and never showed the low voltage lightning bolt. As soon as I inserted the switch between the unit and the power supply, both showed the lightning bolt constantly.So, either these really do prevent enough power from getting to the unit, or just prevent the unit from sensing enough power. (The latter is doubtful.) Either way these are useless to me. I'm not willing to give up valuable voltage for the convenience of a switch.

So far the three that I've used have worked. Push the button, power flows through. Push the button again, and power stops. While it works just fine, it is VERY difficult to tell if power is in the on or off position. This switch really either needs a button that is taller or some other physical way of indicating the on/off position. A small led indicator would have been very helpful. I've included some images to show the difference between the on (up) and off (down) position. Those positions are also counter intuitive from my experience. Check the switches when you receive them and before using them to make sure they are in the desired operational position.