Copy paste from Malaysia Military Times
The hackle is a clipped feather plume that is attached to a military headdress or beret.
The tradition of wearing a hackle was introduced by the British military during the establishment of the Malaysian Ranger Corps in 1963 where, at the beginning, it was used only in the 3rd Battalion of the Ranger Regiment with the 1st Battalion using the hackle in black, the Second Battalion uses a green hackle while the Third Battalion uses a red hackle.
Subsequently in 1975, the Ranger Regiment committee recommended that the use of this hackle be coordinated with all Ranger Regiment Battalions and was approved by the Armed Forces Council (MAT) in 1982. This is something unique for officers and members of the Royal Ranger Regiment (RRR) up till today.
Hackle
Source: Royal Ranger Regiment Wikipedia
Rejimen Renjer DiRaja is the only regiment or corps in the Malaysian Army that is authorised to wear the black hackle as part of their uniform. Also, unlike other units, the No.3 uniform (office duty) has black buttons and Gun Metal pips instead of the standard green buttons and pips of the Malaysian Army.
