Traditionally 3D Printers have used the groovemount system to securely hold a 3D Printer hotend. There are some flaws with this system. The fit is very dependent on accurate machining, and over time the fit can be loose from repeated removal.
To combat these issues E3D Online have developed a threaded system that uses a M12 Thread along with a locking nut on the opposite site. The new system is reliable, repeatable, no wear, and more versatile mounting options. Apart from the change of mounting system, the heat sink is exactly the same as a standard V6 Heatsink.
Please note this is still a beta product.