This is a replacement cap for Showa-era bottled Calpis. After removing the crown cap, you replace it with this cap. Originally, it came with a "Kurono" paper tag, but I found this one without the paper tag while tidying up. I hesitated about throwing it away and opened the bag, but it said "Calpis" on the cap, and I thought it was cute, so I'm listing it in case someone wants it. The bag is torn.