Wilesco Z03 Compressed Air Boiler Adapter Wilesco Dome type whistle D6, D10, D 106, D 14, D 455, D 456.Use this nickel plated fitting to run your Wilesco steam engine on compressed air and still use your whistle with safety valve protection. This fitting is for Smaller boilers that use the Dome type whistle D6, D10, D 106, D 14, D 455, D 456. Fits all newer engines from 1990 on. This valve will NOT fit earlier engines. Does not come with whistle. Click on picture for large view.