It seems like you're asking about an "L key" with a specific size of 5.5mm. An "L key" is also known as an Allen wrench or Allen key, and it is a tool commonly used for turning screws and bolts with hexagonal sockets. The size of an L key or Allen wrench is typically measured by the width across the flats of the hexagonal head, which corresponds to the size of the hexagonal socket it can fit.
So, a 5.5mm L key or Allen key would have a hexagonal head that measures 5.5mm across the flats. This means it is designed to fit into and turn screws or bolts with a corresponding 5.5mm hexagonal socket.
These tools are commonly used in various applications, including furniture assembly, bicycle maintenance, and automotive repair, among others. If you have screws or bolts with 5.5mm hexagonal sockets that you need to work with, a 5.5mm L key or Allen key would be the appropriate tool for the job.
