Which part? The glass is an Epson BT-40 cut in half with some soldering to bypass needing both eyepieces; this cuts the weight & power consumption by ~40%. Mounted onto a printed carbon-fiber nylon frame similar to bone conduction headphones. The computer is a single-board computer I had lying around, but I will upgrade to 12-core 30W SBC next week. The battery is one made for video cameras, and I gave it a belt clip and strapped the SBC onto it. The SBC has camera & mic inputs as well as GPIO for whatever I want to add.