Handhelds and emulation devices are advancing at an unbelievable rate; heck, some of them are now including dual-screens and a hidden stylus to match that of retro consoles of the past, which is going down well with retro gamers across the globe. If emulation is your thing, especially for arcade gamers, then listen up, because a new accessory is ready to pair with your favourite emulator in a way that's incredibly nostalgic.
This is called the Insert Coin Cube by Chronic Concepts; it's a simple accessory that allows you to insert quarters, designed like the classic coin slot in many of your favourite arcade machines, combined with USB connectivity that can be mapped to sync to an emulator in order for you to start a game, just like the good old days. We spotted it over at Time Extension.

Its body is made with an injection-moulded plastic that can house up to five quarters, showcasing a transparent pushable door that lights up, alongside an internal speaker that you can set up to 15 different sounds when a coin is inserted. If none of them tickles your fancy, you can set your own via the web app.
The web app is where you can get real nerdy, thanks to the easy-to-understand UI that offers you the ability to sync with emulators and customise your cube to preserve its battery, which you can prolong by turning on the auto shutdown and activation via coin insert. "Simply connect via USB cable to any PC, Mac, or Linux device and open our configuration website. Our web app is a static web page, not cloud-based, and can be downloaded for offline use forever. No internet or website dependency" states Chronic Concepts.

This is technically Gen 2 of the Coin Cube, featuring different colours, more refined tech and a higher quality shell, and it's the first time we've seen something like a way to integrate nostalgic, retro physical hardware with modern-day emulators and it's incredibly simple to set up as you're literally configuring this as a wireless controller with one button that can be mapped on an emulator.
"Cube functions as a USB-HID keyboard device and works with Linux, Windows, Mac, Retropie, & MAME. Compatible with most systems and software that support USB keyboards. Easily configurable via our web app". This costs just $29.99 via their official website and comes in an array of colours; it's shipping now too!