This is a coil of wires attached to a rectangular 3 inch by 5 inch ARB battery pack which can be strapped or taped to any sufficiently large portion of your outer anatomy. When plugged into an AI/O port, the ARB pack writhes obscenely, generating energy that stimulates your nervous system, making you artificially faster. Use Powers instead of Speed for Initiative.
Having your nervous system hopped up in this way is debilitating; at the end of any sequence in which you've had your neural stimulator plugged in, you suffer 1 point of Impairment. Impairment is cumulative and lasts until after the fight.
Notice that you must have had the stimulator plugged in during at least a part of one one sequence in order to get the bonus, so you will never fully escape the Impairment.