These were purchased in bulk to remove the keyrings and display them as miniatures. I believe they are made of metal, not plastic. The back of the bag has a see-through pattern. They do not open. They have not been used. I don't think they will come apart, but some of the C-rings are not perfectly aligned. Bag size: Approximately 4.3cm wide x 3cm high at the widest points. Mark: Decoration Weight of one piece: Approximately 42g They have some weight to them. Total length: Approximately 12cm Different colors are also available. How about it? Thank you. ※I have pets. ※I am a smoker. Please do not purchase if you are concerned.