1 Dress worn only as authorized by the Commanding Officer. No.4: Warm weather Service Dress (officers only) Issued to officers on first posting to a warm-weather area: the uniform is similar to No.2 dress but made in a light khaki shade defined in Section 01.87 of the Army Dress Regulations as "stone". When officers are taking part in parades and formations with other ranks in warm weather areas, they wear either No.3 or No.6 dress. There had been an Other Ranks pattern of warm weather Service Dress, but this fell out of use after the 1950s. No.6: Warm weather parade uniform (bush jacket) The "bush jacket" uniform (in Australia, this is known as the "safari uniform"). It is issued to all officers and ORs on posting to a warm-weather station. It consists of a stone coloured bush-style four-button jacket worn with or without a shirt and tie underneath and stone coloured trousers. It is worn by all ranks for parades (as with No. 2 Dress), unless No. 3 dress is worn, and by ORs for all other occasions. No.7: Warm weather barrack dress The tropical shirt-and-trousers uniform, consisting of a stone coloured short-sleeve shirt worn with stone coloured trousers (tartan kilt or trews for Scottish regiments), and regimental headgear. Regimental/Corps stable belts may be worn in this order of dress. No.8: Combat Dress The current No.8 Dress, which was introduced as part of Project PECOC in 2011, is known as Personal Clothing System – Combat Uniform (PCS-CU); it is based around a Multi-Terrain Pattern (MTP) windproof smock, a lightweight jacket and trousers with a range of ancillaries such as thermals and waterproofs. Prior to 2011 separate designs of combat dress were provided for use in desert, temperate and tropical regions (numbered 5, 8 and 9, respectively, in the uniform regulations) all of which were replaced by PCS-CU. PCS-CU is designed to be lightweight, yet durable enough to be used throughout rigorous activities soldiers find themselves performing, and with the idea that layers of clothing are warmer and more flexible than a single thick layer. The PCS-CU jacket is always worn loose, with sleeves rolled down; however, an MTP pattern shirt was introduced in 2015 and this may be worn during the Summer months tucked into the trousers with sleeves rolled up. While the shirt may be worn during the winter months, it is always worn with the sleeves rolled down.