All you need is a standard 4" metal electrical box (minimum depth 1-1/2"), and some basic wiring skills, and you can add this fun and functional AC volt meter to your industrial lamp project. When the wiring is tied in with a dimmer, the meter's red needle will move to indicate how many volts are going to your main light (see video). It can display from 0 to 150 volts AC. It works with both LED and incandescent bulbs; but you will probably get the best results with an incandescent bulb. You can also use this volt meter with an on/off switch, but it won't look as "cool" - it will just jump right up to 125 volts when turned on, then back down to zero when turned off. AVAILABLE OPTIONS: The meter is pre-mounted in a 4" raised metal box cover (box not included). You can choose either a natural (unpainted/silver) cover, or one that's painted Flat Soft Iron to match the color of black malleable iron pipe. The original plate opening had two small "ears" for mounting other types of devices - these are very slightly visible on the unpainted cover (see photo #3), but they are less visible on the painted version. If you're looking for a volt meter that can mount directly to pipe, I also offer this same volt meter in a black malleable iron housing - it's mounted inside a 2" merchant coupling, starting at $43.99 (please see separate listing): https://www.etsy.com/listing/889076248/150v-ac-analog-volt-meter-module-for?click_key=5f0a6a25d96e0ae0ed6c9f725a8e1c2731b18ab1%3A889076248&click_sum=c356061d&ref=shop_home_active_27&sts=1 This module includes the box cover, mounting screws, and volt meter only. The electrical box, wires, and other lamp elements you see here are shown for demonstration only and are not included. Photo #7 shows an example of a finished lamp, featuring this part. This is just one of many exclusive DIY lamp making parts I offer here in my Etsy Shop. I also offer exclusive lamp nipple adapters, Apple Watch chargers, power cords, sockets, smartphone cradles, dimmers, glass insulator socket and cord kits, and more. Thanks for looking!