What is the fine-grained topic of the following text: The Caroflow 45-degree Threaded outlet roof vents are manufactured in LM6 Aluminium Silicon casting alloy to BS1490:1970 for most roof finishes as standard or in leaded gunmetal to BS1400:1985 for use with copper-clad or lead roofs or for connection to copper pipework. Only return the topic.
Caroflow 45-degree Threaded Outlet Roof Vents Specifications