Parts for Plastic Bottle Band (Spare Parts)

This is a parts for my daughter's plastic bottle.
I made it because she lost this parts in the Kindergarten.
She's using this for over 1 month, it has still no problem.

Bottle info:
Maker: The Skater Co,.Ltd
Product No.: PSB5SAN
http://dpi.ne.jp/skater/cgi-bin/webcatalog/guest_main.rb?action=detailAction&serial=17305