Center Column Safety for Ulanzi & Coman Zero tripod. 
If you remove the center column extension on a Ulanzi & Coman tripod there is no safety to prevent the head from falling out of the tripod. This is a small safety stop to prevent the center column from sliding out and it has an o-ring if you wish to attach a weight to your tripod. You will need a long 3mm allen wrench to attach the safety stop to center column.