The Efferent Suppression Cuff is a rigid polymer band, twelve centimeters wide, applied to a limb proximal to a traumatic injury to interrupt motor nerve conduction in the affected region without interrupting sensory or autonomic signaling. Where a conventional tourniquet manages blood loss through mechanical compression, the Cuff manages neurogenic shock and uncontrolled muscular spasm through targeted bioelectric interference — a low-amplitude pulsed field tuned to the efferent nerve frequencies documented in Zheng-Dao's proprietary human neural atlas. The result is a limb that can no longer generate voluntary or involuntary muscular contraction distal to the Cuff, while retaining circulation and sensation. This is particularly valuable in crush injury and blast trauma scenarios, where involuntary muscular activity in a damaged limb can worsen internal bleeding and complicate extraction.

The Cuff's selective interference profile is its defining engineering achievement. Early-generation nerve suppression devices — some of which still circulate in the outer ring — used broadband electrical interference that suppressed all nerve conduction indiscriminately, creating a limb that was numb, pulseless, and increasingly ischemic. Zheng-Dao's efferent-selective approach, refined across four hardware generations, preserves the autonomic signals that regulate vascular tone, preventing the vasoconstriction that caused ischemic complications in earlier devices. The Cuff can be worn for up to four hours without clinically significant nerve damage in healthy tissue; in compromised tissue, Zheng-Dao recommends two hours and documents the rest as acceptable liability.

The device has a civilian medical license in GLMZ's mid-ring districts and is standard equipment in Zheng-Dao's own corporate medical facilities. It also has a significant off-label market: the same efferent suppression field that prevents a trauma patient from thrashing through their own injury can, at modified power settings, be used to incapacitate a limb with surgical precision. This application is not discussed in Zheng-Dao's product documentation, but it is discussed extensively in the parts of the city where the Cuff is known as The Quiet.