If you own a Hornet or Grasshopper, this set will allow you to print a battery door and retainer (for the Hornet, the retainer is also a trans brace) that will make the battery stay put. Please see the videos below to see how this set is installed on a stock Grasshopper or Hornet (or Grasshopper with Hornet rolling rear axle). You can print a stock look battery door, hornet printed one or grasshopper printed one. There are also two styles of trans brace (one for the original hornet with the Grasshopper "tab" trans and one for the re-release Hornet with the Midnight Pumpkin "no tab" transmission).