A Launcher Grip is an accessory that can be attached to the back of the Ripcord or String Launchers. They are used to make launching the Beyblade more accurately and easier. They can come in a variety of colors. (not including the wide variety of colors of ripcord/string launchers).
Takaratomy Japanese Beyblade Launcher Accessory #BB-61 Grip Rubber - Red - B002SNAKXE