The armed forces officer and non-commissioned officer normally wears a mess uniform equivalent to the civilian black tie and evening dress. Stylistically, the mess uniform varies according to the wearer's regiment or corps, but usually comprises a short Eton-style coat reaching to the waist. Some include white shirts, black bow ties, and low-cut waistcoats, while others feature high collars that fasten around the neck and corresponding high-gorge waistcoats. Usually, mess uniforms are brightly-coloured (in the British Army scarlet is most common) and ornamented with gold and lace and gilt buttons, all corresponding to the colours of the regiment or corps of the wearer. In the Royal Navy there is a distinction between "mess dress", which is worn at white tie events, and "mess undress", which is worn at black tie events. Both are worn with a black bow tie, however mess dress is worn with a white waistcoat instead of the usual colour, and may be worn with a stiff shirt and wing collar. The stiff shirt and wing collar were abolished for mess undress in the 1960s, and were made optional for mess dress in the 1990s. Red Sea rig In tropical areas, primarily in Western diplomatic and expatriate communities, the jacket and waistcoat are sometimes omitted and a cummerbund substituted. This form of black tie is known as Red Sea rig.