For still smaller quantities or pure gases or specified mixtures, products are supplied in gas or "liquid cylinders" ("packaged gases"). Liquid products from the production plants are either filled directly into smaller cryogenic containers, or are pumped to high pressure, vaporised and filled into HP cylinders; gaseous products are compressed to the required pressure for cylinder filling. These trans-fills are carried out in special filling depots. The distribution to customers is normally by road transport. Some depots are also equipped to make gas mixtures to customer specifications. In the case of acetylene, the product is compressed directly into cylinders at the production plant.
The European industrial gases companies fill, store, transport, and maintain an inventory of approximately 35 million cylinders to serve the market.