Mei-Shun tried to change filter of a water purifier by herself. She has asked Shin to do it, yet such a chore seems to be for the wife. Oh, here is a spare which he tried to find in his study. Now 3 others are ready, 3 years guaranteed in future. However, older one never moves even if twisted by her all-thumb hands. She told it to the husband, who used only a second to remove it.