A lip channel is a type of structural steel that features a distinctive L-shaped profile, which enhances its load-bearing capabilities. The dimensions 150x65x15mm refer to the overall size of the channel, with the first number representing the height, the second the width, and the last number indicating the thickness of the material. Mild steel, known for its ductility and strength, ensures that these channels can withstand various environmental conditions, making them ideal for roofing applications.