The Ikan EV2 Grip Handles with 15mm Rod Adaptor (200mm Core, Pair) has a 200mm size solid metal cores that comes out on both ends the handle. It also comes with the 15RDA ELEMENT piece already attached and a spring loaded ratcheting thumb screw(s). Simply slide the handle onto a 15mm size rod and tighten the thumb screw.
The position of the handles can also be adjusted on the core, loosen the four screws on the side of the handle, put the handle in the desired position and then tighten. If your handle is put in a position to where you cannot loosen or tighten the thumb screw, pull up the thumb screw and adjust.