It looks like an S&L imo (u/m '4' )
"In all my years as a soldier, I have never seen men fight so hard." - SS Obergruppenfuhrer Wilhelm Bittrich - Arnhem
HÝ Nick, this not S&L this is a unmarked 55 Hammer & S÷hne
I'm looking for EK II 1939: B.H.Mayer: A and B core,mm L/18 and schinkel type ,,,EK1 Round-3 with Deschler frame and Friedrich Sedlatzek pin and SB variant
Here is a maker marked '55' for comparison.....
Thanks for help