The MEDISTOCK Helix Test reproduces the most demanding sterilization conditions for a narrow-lumen hollow instrument (type A load), simulating the most difficult steam-penetration path. The reusable, coiled device closes with a single-use chemical indicator inserted into its capsule; after a full cycle at sterilization temperature, a uniform color change along the entire length of the indicator confirms that steam has penetrated the whole device. This check is typically performed once a day, on an empty chamber, before the first load cycle, alongside the Class B autoclave's other routine indicators. Pack of 100 indicators, compliant with EN 867-5 (hollow-load process challenge devices) and ISO 11140-1 (chemical indicator classification).