Authorized headdress for the Canadian Armed Forces are the: beret, wedge cap, ballcap, Yukon cap, and tuque (toque). Each is coloured according to the distinctive uniform worn: navy (white or navy blue), army (rifle green or "regimental" colour), air force (light blue). Adherents of the Sikh faith may wear uniform turbans (dastar) (or patka, when operational) and Muslim women may wear uniform tucked hijabs under their authorized headdress. Jews may wear yarmulke under their authorized headdress and when bareheaded. The beret is probably the most widely worn headgear and is worn with almost all orders of dress (with the exception of the more formal orders of Navy and Air Force dress), and the colour of which is determined by the wearer's environment, branch, or mission. Naval personnel, however, seldom wear berets, preferring either service cap or authorized ballcaps (shipboard operational dress), which only the Navy wear. Air Force personnel, particularly officers, prefer the wedge cap to any other form of headdress. There is no naval variant of the wedge cap. The Yukon cap and tuque are worn only with winter dress, although clearance and combat divers may wear tuques year-round as a watch cap. Soldiers in Highland, Scottish, and Irish regiments generally wear alternative headdress, including the glengarry, balmoral, tam o'shanter, and caubeen instead of the beret. The officer cadets of both Royal Military Colleges wear gold-braided "pillbox" (cavalry) caps with their ceremonial dress and have a unique fur "Astrakhan" for winter wear. The Canadian Army wears the CG634 helmet.