Sky's Edge products/designs are distributed under the Creative Commons Attribution/Share Alike license (CC BY-SA) with the following additional stipulations:
1. The derivative product must be modified (ideally, improved) in some way. It should not be produced from my design files exactly. The point of the open source spirit is cumulative improvement through community effort. Do not take designs from Sky's Edge and resell them exactly as-is.
2. Derivative products MUST BE CALLED SOMETHING OTHER THAN WHAT SKY'S EDGE CALLS IT. The name of your version of the product should not include any part of the name that Sky's Edge used. I insist on this because of the confusion of what I'll call "namesharing" causes in the world of open source hardware. Examples of why this is important: Turtlebot, Turtlebot 2, and Turtlebot 3 are each different group's take on the same project, but by each new organization/company naming it sequentially like that it makes it look like these forked projects are each newer versions of the Turtlebot, whereas that's not the case at all; they're just different flavors. Another example is the Pixhawk flight controller for drones. I could write a dissertation on that mess. Hardware naming should be done like Linux distributions where Each new flavor gets its own unique name, but people can find out that Ubuntu (for example) is based on Debian.