Rubber necklaces with titanium pendants . They are closed by means of a peg that clamps the cord. This system we recently improved significantly. Nowhere is the closure to see but if you let the cord slip through the fingers keenly felt. Straight pull open and not run. The rope thickness is 3.5 mm. We use 45 cm as a standard length. But there are longer and shorter cords in stock.
Of the first three models, the front and back sides different colors and can be reversed so you have another colored necklace.