I bought an E3 with two pan heads. The locking lever came off completely and failed to lock the bullet at all after a few uses. Additional Info: The E3 I bought was an older product and I couldn't find it on Revain anymore. But it uses the same locking structure as this one. The problem is that once the locking lever is loose you can't tighten it and you can't remove it. Everything becomes garbage and money is wasted. The design is wrong from the start. Be careful if you want your investment to last a while. In addition, you do not have the opportunity to find out the contact details of the seller. It's hidden somewhere in China.