product details Material: alloy; Process: electroplating, epoxy, discoloration Ring size: opening (adjustable type) (minimum size 17cm, maximum size not limited) The principle of changing color: the color changes with temperature, the color is black below 14 degrees and the different colors change between 14 and 37 degrees. Precautions: 1. The dry temperature range that the ring design can withstand is 0-38 degree, avoid exceeding the maximum temperature set by the ring, which will damage the color changing material; 2. Avoid hot water (because the discoloration interface is glue cover, it will damage the high temperature discoloration material, and at the same time, it will produce thermal expansion and contraction effects, which will damage the air and water; Third, avoid bumping into yourself