German WWII Luftschutzkeller Sign

German WWII air raid wooden sign.  This came with a vets items recently picked up.  Wooden sign that says "ZUM LUFTSCHUTZKELLER" painted in black paint.  It measures 12 3/4 inches long and 7 1/2 inches wide.  In nice shape and has two small nail holes in each top corner.  On the back is a name "Sgt Lock? and cannot read the rest.  Also some month and dates, but they are in English so not sure when they were written.  Nice display.