The external batteries can be made to work for the LR-2 system but will require some effort rigging them.
The EXTERNAL battery pack for the LR-2 system consists of the batteries and a fragile wiring harness terminating in a male plug for adapting to the LR-2 receiver/camera and a female plug for charging. If used as shipped, the battery pack will "dangle" from the receiver/camera by the fragile wiring harness. Unfortunately, this was not well thought out. I used electrical tape to reinforce the plug leads and to secure them to the the battery packs. I then used Velcro to secure the battery packs to the the camera/receiver to eliminate the "dangle". The only reason I would recommend the EXTERNAL battery pack system as currently configured is that you really don't have any choice if you want to extend the run time for your LR-2 system. LongShot really needs to re-think the configuration of the EXTERNAL pack before I could recommend it.