A portable, biometrically-secured device for facilitating various different types of in-person and online transactions. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. As a sender transmits the message, a message-to-reply field will be incorporated to the message, and a reply field will be added after the recipient opens it. The heating jacket is arranged in or on a fluid-permeable supporting hollow body.