This is one of the most incredible pieces of trench art we have ever encountered.
As a first note: every collector needs to be very careful with trench-art, because there are fakes out there, very good ones. This piece however is what in the collecting world would be called a one-looker.
It also has an excellent pedigree. It was found by a Swedish collector in the 90s, then sold by Military Stockholm Antiques around 2003 and remained in the same collection for 20 years. The piece itself is the shell casing from a signal's pistol.
It is 5 cm in length and 3 cm in diameter. The engraving has been beautifully and carefully done. It has a skull, a Wolfsangel, the words "De Ruiter", and the place "Zuid Kalleten" (Dutch spelling) and date. On the bottom, it has been marked with the initials of the owner, who was probably originally a member of the Dutch Legion (hence the Wolfsangel) and later served in SS-Freiwilligen-Panzer-Grenadier-Regiment 49 "De Ruiter".
An absolutely unique museum-quality piece from a Dutch volunteer who participated in the famous Kurland battles.