Thank you for taking the time to contact us.
All of our plastic sheaths contain some glass content. The only sheath that has changed is the BK2 sheath. The newer sheath for that item number has slightly less glass content than previously made sheaths. All distributors should have new product at this time, as the new sheaths were introduced over a year ago. Also, I would recommend pulling the knife straight out of the sheath, instead of rolling it along the side when you extract the knife from the sheath.
The sheath for the BK13 and the sheath for the BK 11 have never been changed. All new product will be introduced in mid-January; however, I would recommend checking our website or our Facebook page regularly for updates and announcements.
If you have any other questions, feel free to contact us again.