This review by L’Antre du Dingo compares two 100% mechanical HPA drop-in units from MechLabs: the NEXXUS and the updated XX-MOD. These systems are unique because they provide semi and full-auto fire without any batteries or electronics, making them immune to water damage and electrical failures during gameplay. While the units are well-machined and visually impressive, they are primarily marketed toward the speedsoft community.

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.

iiAnferny presents his airsoft rifle built with the Nexxus mechanical engine from Mech Labs at Gamepod, showing its advanced, air-efficient performance akin to the Arc platform. Designed for customization, it's compatible with most M4s using a V2 gearbox and suits various configurations, including speedsoft builds. Fully mechanical and battery-free, it delivers fast trigger response with semi and full auto capabilities, firing over 3,000 shots on a standard HPA tank.

Dexter Airsoft shows the various features of the Nexxus HPA Gearbox in this video... "I am very excited to show you this latest inovative piece from Mechlabs, a fully mechanical HPA gearbox, in V2 formfactor.

With no batteries required, adjustable Rate of Fire, and a tactile trigger feel, this gearbox is worth the price!"

At the Mechlabs' booth during the MOA Exhibition Taiwan 2024 is the Nexxus HPA Engine that is a powerful, battery-free upgrade for your M4/AR15. This full-mechanical engine offers both semi-automatic and full-automatic fire modes, activated by a simple selector switch. Powered by an HPA tank, it delivers ultra-fast trigger response and impressive efficiency, capable of firing over 3000 shots on a single 48/4500 tank fill.