Ascender Zero is a wheel that climbs steps on its own — with no motor, no sensor, and no battery. On flat ground, it stays firm and round, rolling like a normal wheel. When it meets a step, the tire flexes around the edge, climbs over, and returns to its round shape by itself. It climbs the steps that block daily life — door sills, thresholds, and curbs. A 10-inch wheel climbs a 5-inch step — 100% of its radius. Each wheel weighs under 3.3 lb and supports 110 lb. The entire climbing system fits inside the wheel, so a manual wheelchair, walker, stroller, or cart can climb steps by changing its wheels. There is nothing to charge, nothing to set up, and nothing to break. It can be fixed with basic tools and works anywhere — even where there is no electricity. Less technology, more freedom.