Description
Lonex L4-A1 Full Gearbox Set (SP150 Ultra Torque Type)
This is a complete, ready-assembled Lonex gearbox in its SP150 Ultra Torque Type configuration. Lonex produces a wide range of AEG internal parts, and its full gearbox sets are designed to drop in to M4-pattern AEGs as a whole, upgraded unit.
The Ultra Torque Type is geared for pulling a stronger spring, here an SP150, rather than for outright rate of fire. It suits players building a more powerful, longer-range rifle, such as a designated marksman setup, where consistency and reliability matter more than speed.
Build and internals
Lonex’s complete M4-A1 gearbox sets are described by retailers as being built on a Version 2 shell with 8mm ball bearings, an enhanced steel gear set, a polycarbonate piston with steel teeth and an aluminium piston head, a steel cylinder, a steel ball bearing spring guide and low-resistance wiring. Because the set arrives assembled, you avoid the time, tools and shimming needed to build a gearbox from loose parts.
Choosing a type
Lonex offers this set in several versions: the SP100 High Speed Type for rate of fire, the SP120 Original Type with a standard ratio, and this SP150 Ultra Torque Type for stronger springs. A stronger spring means more power, so it is essential to check the output with a chronograph and make sure your rifle is within the limits of the site you play at. Many sites have different limits for full-auto rifles and for semi-only marksman rifles.
Fitting
Swapping a complete gearbox means stripping the lower receiver, so remove the battery and magazine first and note how your existing wiring is routed. Check whether your replica is front- or rear-wired before ordering. After fitting, set the motor height for a smooth, quiet note and test the gun with a chronograph before taking it to a game.
Key features
- Complete, assembled Lonex gearbox set
- SP150 Ultra Torque Type configuration
- Geared to pull a stronger spring
- Version 2 design for M4-pattern AEGs
- Steel gears and ball bearing spring guide (per retailer listings)
- Low-resistance wiring
- Drop-in replacement for many M4 AEGs
Compatibility
Designed for M4-pattern AEGs that use a Version 2 gearbox. Small differences between manufacturers’ receivers mean some bodies may need minor fitting work, and some may not accept it. Check whether your replica is front- or rear-wired, and ask us before ordering if you are unsure which configuration you need.
Care and maintenance
Use good-quality seamless BBs and a battery and motor suited to the gearbox. Fire a shot on semi-auto before storing the gun so the spring is not left compressed. Keep the inner barrel and hop-up clean, and have the gearbox inspected and re-greased if you notice changes in sound, rate of fire or trigger response. Stronger springs put more load on the gearbox, so regular inspection is especially worthwhile with this version.
Who is it for?
For experienced players building a higher-powered M4-pattern AEG, such as a marksman rifle, who want a ready-built gearbox geared for a stronger spring.
Please note: Motor, battery and outer parts are not listed as included. Check your power output with a chronograph after fitting and stay within your site’s limits. Sites often require marksman-level power to be used on semi-auto only.
