Experimental. These circuit boards are used by the OLHZN High Altitude Balloon team for high altitude weather balloon tracking. However, the circuit boards are considered experimental and may suffer from unforeseen errors or undiscovered technical deficiencies. An amateur radio license from the FCC is required to operate these in the United States and many other countries worldwide. Check your local governing body for details. Due to the experimental nature of these circuit boards, returns are not accepted on this product. The bare circuit board is the least expensive option, but you would need to purchase the assembly parts yourself. The source code, parts list and assembly instructions can be found at https://github.com/OverlookHorizon/OLHZN_Track If you want to have all the parts included or have the board pre-assembled for you, you may select those options too, if desired. They are not required, though. You can source the parts and build the entire board yourself for the lowest cost.