Made By Optimum. IRB Approved. Closed cell foam padding, laminated construction and plush chin strap ensure maximum protection and comfort. The colors are insipired by the South African flag and the name Bokka is taken from the South African mascot, the Springbok. Headgear should fit tightly, yet comfortably. To determine the correct size, measure the circumference of the head just above the ears with a measuring tape.