Push down in the center with a small philips Head. either the sides will push up and allow you to grab one, or you’ll poke a hole in the center which will give you access to pull it out.
If you’d just end your comment with quod erat demonstrandum (or Q.E.D.), then we’d all know you’ve had the final say and there’s nothing more to contribute?
14mm male wpa so standard fitting. Mine fits perfectly in a 14/18 glass adapter and use it with a j hook. I’ve seen wood pipes with a 14mm female connection and those would work also.