The Reactive Shear Mantle is a mid-weight ballistic garment built around Arcturus's shear-thickening fluid suspension, housed within a flexible outer membrane that resembles a heavy-duty technical jacket at rest. Under low-velocity contact the material flows and conforms normally, allowing full range of motion. When struck by a high-velocity projectile or blade, the non-Newtonian fluid instantaneously hardens in the impact zone, distributing force across a palm-sized area before returning to its flexible state within fractions of a second. The transition is imperceptible to the wearer in most engagement scenarios.

The Mantle's outer membrane is treated with a ceramic particulate coating that ablates incrementally under sustained fire, buying additional time against automatic weapons before the fluid suspension is compromised. Arcturus markets this as the 'dual-envelope' protection philosophy — the ablative exterior handles the first wave while the reactive core manages penetrators that break through. A chemical indicator strip on the interior collar changes color when fluid suspension integrity drops below operational threshold, giving the wearer a passive readiness check without powered diagnostics.

The Mantle occupies an unusual market position: it is formally classified as personal protective equipment rather than body armor in several jurisdictions due to its non-rigid construction, allowing it to be worn and transported in contexts where plated armor would be flagged. Arcturus has cultivated this ambiguity carefully, and the legal designation is part of the product's value proposition in cities with aggressive gear-check enforcement. Corporate security details, investigative journalists operating in hostile zones, and high-risk financial couriers are among its more visible user populations.