What is g400?

As an AI language model, I cannot determine what precisely you are referring to as "g400." There are multiple things with this name that have different meanings. Therefore, here are some common interpretations:

• G400 is a model of golf clubs by brand Ping that includes drivers, fairway woods, hybrids, irons, and wedges. This golf club set is intended for players who require more distance and accuracy off the tee.
• G400 is a type of aircraft produced by Gulfstream Aerospace, which is a business jet that can operate long-haul flights with a crew of two pilots and up to 19 passengers. It has a range of 4,630 nautical miles (8,573 km)
• G400 is a type of gaming mouse produced by the computer hardware company Logitech. The mouse has sensitive scroll wheels, advanced optical sensor technology, customizable sixth and seventh buttons, and programmable RGB lighting.

If you meant something specific, could you please provide more context or details regarding what you meant?