The ShieldTech CS-3 CryoStop is a contact cryogenic agent delivered in a high-pressure aerosol system. The active component is a rapid-expansion liquefied gas blend — a proprietary mixture of compressed dimethyl ether and supercooled tetrafluoroethane — that undergoes extreme adiabatic cooling upon release from the canister nozzle, reaching contact temperatures of -78°C to -95°C at the point of application. When directed at exposed biological tissue — skin, particularly the face, hands, and neck — the cryogenic contact produces immediate intense pain (cold allodynia response), involuntary muscular contraction, and rapid numbness as surface nerve endings are temporarily desensitized. Extended application to a single area causes superficial to moderate frostbite injury. The effect on an unprotected subject is immediate and profoundly disabling — the pain response alone is sufficient to interrupt most physical actions.

The CS-3 is positioned by ShieldTech as a situational compliance tool for scenarios where conventional aerosols are contraindicated — specifically, environments where chemical agent contamination is undesirable (medical facilities, server rooms, food handling areas) or where a subject's respiratory augmentation makes inhaled agents ineffective. The cryogenic agent disperses rapidly in open air, leaving no chemical residue and producing no lasting environmental contamination. It is also effective against some augmented subjects in a way that OC and CS sprays are not: while chrome limbs are unaffected by the cold, exposed biological tissue anywhere on the body — face, neck, the bio-mechanical interface zones — is as vulnerable to cryogenic pain as in an unaugmented person.

ShieldTech's safety documentation is extensive and explicit about the injury risk of the CS-3. Prolonged application — more than two seconds to a single area — risks frostbite injury. Application to eyes risks permanent corneal damage. Application to ears risks damage to the tympanic membrane. The product is sold with a clear warning that it occupies the boundary between less-lethal and injurious tools, and that operator training is mandatory for institutional purchasers.