The meaning of "JK" is unknown. Because it is thick and durable in resin, it is useful for storage of small classified chemicals. As a lazy worker, it also plays an active part as a shampoo and soap pouch when traveling. I am very happy with the price.
Because it is made of resin, the influence of chemicals does not come out is the deciding factor of purchase. This is convenient when opening and closing frequently because the mouth is thin. Because the price is very cheap, it can be used as a consumable as it is easy to use. For replenishing, large models are better suited.