Bamboo socks from Umbrella Underwear. Knitted from soft bamboo yarn together with a nylon thread, which ensures reinforcement of the toe and heel and with an elastane thread that gives a good stretch and makes the stocking keep the shape washed after washing. Unlike most other bamboo socks on the market, these socks are plugged into a double-cylinder knitting machine. This means the socks is more sturdy and comfortable than a sock from a single-cylinder machine. The toe is closed automatically with a stitch that does not generate – even in tight shoes.