Laurens Rup(p)ert, was a clockmaker from Mainz, he married Maria van
Meurs, the daughter of the important clockmaker Otto van Meurs in 1760.
Stylistically the painting on the mask is very close to two painted masks signed J.H. Strumpff, illustrated in: J. Zeeman, De Nederlandse Staande Klok, Zwolle 1996, pp. 135 & 137.
The case is typical of models made in Amsterdam between 1750 - 1765.