Staff sergeant major[1] is an appointment in some Commonwealth armies and also a rank in the Royal Canadian Mounted Police.
Staff sergeant major (SSM) is an appointment in the British Army held by warrant officers class 1 in the Royal Logistic Corps who are not conductors or regimental sergeant majors.
Staff sergeant majors existed in the Army Service Corps and Ordnance Store Branch in the 19th century.
In 1892, conductors of supplies in the Army Service Corps were renamed staff sergeant majors 1st class.
Like the conductors, they wore their royal arms rank badge in a wreath.