Just bought a Rocky Mountain Dirt Jumper, not sure about the exact model because the previous owner custom-painted it. It is missing a pedal and I noticed that the crankarm wasn't threaded like a normal crankarm, but instead, had some threads that went straight from the top to bottom, and I saw on the other crankarm, there was some sort of adapter that was attached the the crankarm, which also had the pedal attached to it. Wanted to find out what it is and where I can purchase one.
Update: Took apart the crankset and I found this, wondering if this works with any types of cranks?enter image description here