We unbox, set-up and review the Critical XR & XR-D tattoo power supplies and talk you through their features, as well as looking at the similarities and differences between the two. The XR & XR-D are the latest power supplies from Critical and are now available to order from Killer Ink. Each power supply offers a new full colour TFT display with user-selectable colour themes and large easy-to-read fonts. Both the XR & XR-D feature a billet aluminium CNC-machined housing with a responsive touch user interface. The Critical XR-D model also has a built-in oscilloscope for a visual approach to coil machine tuning. The jump start feature and maintained pedal modes for each power supply are now independently assignable to preset/output buttons.