A red cord bracelet is about as simple as jewellery gets, and it is one of the most common objects in Chinese daily life. The knot used here is a flat weave, made by hand on a small frame, and the closure slides so the bracelet adjusts instead of needing a hook.
The cord is braided polyester rather than silk: it is colourfast, it does not fray in water and it will survive a shower. Washable in cold water; the weave tightens slightly with wear.