https://www.youtube.com/watch?v=wa_iZASGv4o

CL-801S   Magnetic socket inserts
●For SAE sockets.
●Magnetic insert holds the fastener firmly in the socket.
●Magnetic insert can be removed from the socket and reinstall in other sockets easily.
●SAE size: 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16" and 7/8".