This Bergeon 4040 movement holder is reversible, with the large size (quite versatile) holding movements between 8 ¾ ligne (20 mm) and 19 ligne (43 mm) in size. A Swiss-made classic, the 4040 is Chromium-plated and sanded to remove any rough edges. It weighs 40 gr. and is 47 x 38 x 22mm in size.
An alternative to the metal Bergeon 4040 is the Bergeon 4040-P, which is a synthetic plastic holder. It handles the same range of watch movement sizes, differing only in material (as a result, weighs only 15 gr). We should note that a large number of owners of this hardened plastic model have been dissatisfied, finding it is unable to hold the movement as well as the original 4040, with the movement twisting or slipping. If deciding between the two, we recommend sticking with the classic Bergeon 4040 .
Here is a video from Esslinger to show the Bergeon 4040 in use: