Rainshadow Airsoft shows the installation of the new Nexus mechanical HPA engine from Mech Labs into a Krytac LVOA. He unboxes the Nexus engine, its components, and the minor modifications needed for installation, such as replacing the selector switch and plate. The installation process involves swapping selector parts, dropping in the engine, and modifying the grip. Included in this video are testing, field gameplay footage, and the sharing positive impressions of the engine's trigger response, tactile feel, and accuracy.