There are two boiler drain tools for the various Ladybugs. If you have a Ladybug® 2350 TEKNO®, then the tool you need is a 6 mm hex tool. While the TEKNO comes with this tool, you can use any 6 mm hex wrench, socket or T handle.
All other Ladybugs (2300, 2200 and 2150) use a 21 mm socket. This is the tool that is included with your Ladybug.
You can also use a 21mm deep socket.