Slimline™ hot water radiant baseboard heating panels are aluminum extrusions with 3/8" copper pipe running through them. The copper pipe protrudes 3" on each end, which allows the use of either copper or PEX Pipe for the panel connections. The Slimline™ comes with a durable white finish that is guaranteed not to rust. If different colors are preferred, the panels can easily be painted after installation with an oil-based enamel.