The traditional dinner jacket is made of black wool, with ribbed-silk or satin lapels but without vents. The lapel can either be the peaked lapel as seen in the evening tailcoat, or the shawl lapel associated with a smoking jacket
. If you choose the peaked lapel, it is immaterial whether the jacket is single or double-breasted. (in the UK, it is considered incorrect to have more than one button on a single-breasted dinner jacket). The third type called Notched lapels is an American innovation but considered by many as inappropriate and informal.