For senior rates petty officer and above, No. 1 Dress consists of a similar double-breasted jacket to commissioned officers except with only six buttons. Historically, this was originally known as the 'long jacket', and was first introduced for engine room artificers, masters-at-arms, and schoolmasters. Later, its use was extended to all Chief Petty Officers (1879) and Petty Officers (1920). Relevant rate insignia is worn on the left arm of the jacket by petty officers. Like their counterparts as worn by commissioned officers, it is divided into 1A, 1B and 1C dress. In 1A dress, when armed, a white web belt and white gaiters are worn by senior ratings as they are by junior ratings. WO1s wear a sword and sword belt with 1A dress. However this differs from that worn by commissioned officers in that it has a black grip instead of a white one, and it has a plain stepped pommel instead of the officers' lion mane one.