B3/BN783 is a metric, single-handed thumb screw manufactured by Bossard. It consists of a socket-head cap screw with a fixed knurled head, or thumb piece, that can be rotated with the fingers to tighten or loosen the screw. It is made of steel with a zinc-plated finish and is available in both right and left hand threads. The head diameter is 6.5 mm, the thread size is M3, and the length ranges from 10 to 50 mm. The B3/BN783 is used in a variety of applications, such as fastening electrical components, affixing panels, and serving as a pivot point in furniture assembly.