The Brachial is a Collaboration from Microtech Knives and Bastinelli Knives, this model filled a gap in Microtech production as they did not offer any type of upswept persian style folder. The Brachial roughly resembles the Bastinelli Knives "Chopper" model and works very well as an OTS Auto. This collaboration never saw to many versions beyond the standard production variants. 

Other Bastinelli collabs include:

The Iconic Auto

The Iconic Fixed Blade

The Feather Fixed Blade 

The Hypnotic Fixed Blade

The Explicit Fixed Blade 

The Brachial Auto

From the Microtech website:

Inspired by the fine curves of Persian blades, the Brachial auto is a collaboration with Bastinelli Knives and is a versatile knife that can be used for hunting, utility and self defense. Microtech exclusive automatic opening technology makes for fast and strong deployment.