One Step Co., Ltd.'s Air Disaster Prevention Division, which develops, sells, and rents products for disaster prevention, disaster mitigation, and safety management, has developed a new “Inflatable Rapid Water Storage Tank for Firefighting” that enables quick securing of water sources at disaster sites and during firefighting operations. The product will be available from May 15, 2026. The new product improves on a conventional model that has been adopted by the Yokohama City Fire Bureau, newly incorporating a robust drop-stitch structure. It is a next-generation relay water tank for firefighting that combines the ease of an inflatable product with rigidity comparable to a hard case and expanded capacity. It can be set up faster than previous models, improving mobility at firefighting sites where every second counts. Development Background: Securing Water Sources in Narrow Areas and Forest Fires In increasingly frequent large-scale fires, securing and relaying water is a critical issue in densely packed residential areas and forested regions where fire trucks have difficulty entering. Relay tanks that temporarily store water near the scene must provide maximum capacity in limited spaces while allowing fast transport and installation. Three Key Features of the New Product While retaining the convenience of an inflatable design, the product adopts an innovative structure that maximizes on-site usability and durability, based on demonstrations with fire departments and interviews with firefighting professionals. 1. High Rigidity Through a Drop-Stitch Structure The tank uses a drop-stitch structure in which the inner walls are connected by tens of thousands of special polyester threads. When inflated, the PVC tank becomes as hard and strong as a board. 2. A Perfect Square Shape That Eliminates Dead Space Because the drop-stitch structure allows the walls to stand vertically, the tank maintains a perfect square shape. The wall thickness has been reduced from the conventi