Friction armband and codes. MK2 friction armband with two khaki cotton cords. This accessory is intended for special troops. A small 28x26cm silk square on which are printed around thirty codes for the months of March, June, September and December. Friction armband and codes. Friction armband MK2 with two khaki cotton tie cords intended for special troops. A small silk square 28 by 26 cm printed with about thirty codes for March June September December.