KA Bamboo Circular Needles. KA are a bamboo circulars that come in a full range of sizes and lengths. They have a clear plastic cable and the needles are bamboo. The KA are functionally superior in needle, join, and cable. The needle is very light, with a polished and silken feel, the needles are cut on the straight grain from bamboo heartwood and they are harder than typical bamboo needles.