Stock coil universal found in many engines like the GY6 and CN250 engines as well as mini Honda style ATV, Motorcycles and Go carts.
Very universal and very generic that gets the job done.
Stock coil for both 50cc and 150cc scooters go carts and atvs.
To test to see if you have spark remove spark plug and attached to coil and ground out to frame you should see spark when you try to start.
CDI tells the coil when to fire from pluse from magneto. Usally when you are not getting spark and plug is good a coil or cdi could be bad.
The pulse from magneto travels to CDI which releases ground from coil and lets coil fire plug, there should always be 12v at coil and when pulse goes to CDI the CDI reases ground and 12v to let coil fire its voltage to plug.