I don't know which unit Justin uses but the Boss WL20 is a simple 2 unit system and very reliable.
Main Features
Plug-and-play wireless systems for guitar and bass
No complicated setup required-simply dock the transmitter and receiver together for about 10 seconds to set the optimum wireless connection
Newly developed BOSS technology delivers premium audio performance with rock-solid stability, ultra-low latency (2.3 ms), and 50-foot/15-meter range (line-of-sight propagation)
Built-in rechargeable batteries provide up to 12 hours of continuous playing time
Simple charging with a standard USB adaptor (5 V/500 mA or greater)
Cable tone simulation reproduces the natural capacitive effect of a 10-foot/3-meter guitar cable
Spare WL-T Transmitter available separately
Plug In and Rock
A WL-20 system is literally as simple to use as a standard guitar cable. The small transmitter plugs into your instrument, while a matching receiver plugs into a pedal or amp. That's it!
This unit has a cut out switch on the guitar transmitter that cuts the sound when it's unplugged so you don't have to turn the amp down first. A very handy feature. UK price £165.00
https://www.absolutemusic.co.uk/boss-wl ... ystem.htmlBarry