Basically a simplified version of the RadioPi Zer0 I designed earlier. The GPH Zer0 (General Purpose, Headless) was designed around the idea of being a wireless, "lightweight server" so to speak.
With that being said, the the design varies from the RadioPi Zer0's in that the antenna has been removed, along with the case being highly ventilated. The case has as well been shortened by 2.5mm. The USB cover was removed from the design due to the fact if this is to be used often, (Plugged in and left on for days) the cover would most likely be never used, and probably would get lost.
I've been running this as a little Pi-hole DNS server with no issues. Running for several days, the device barely gets warm. Case and point though; this device can be used for many applications, and it's small size make it great to to plug in behind a computer, or near a router.
Raspberry Pi Zero W: https://www.adafruit.com/product/3400
USB A Addon Board: https://www.amazon.com/MakerFocus-Raspberry-Required-Provide-Connector/dp/B077W69CD1?tag=tv-auto-20
MicroSD Card: https://www.amazon.com/Sandisk-Ultra-Micro-UHS-I-Adapter/dp/B073K14CVB/ref=sr_1_3?crid=1QTX1Y34ANTZT&keywords=16gb+micro+sd+card&qid=1558389825&s=gateway&sprefix=16GB+mi%2Caps%2C158&sr=8-3
M2.5 x 8 Screws: https://www.amazon.com/Socket-Screw-Assortment-Internal-Washer/dp/B0116PZDWC