MG Ammobox with painted markings

[Jørn Schmidt]

I have just picked this MG steel ammobox up,sadly it does have some rustspots,but a lot of the fieldgrey paint are still present,
the box are marked on the top,with number-white cross and then its marked SS-Lsp,can anyone here tell me what Lsp means,
cut it mean Leuchtpistole?,because the box might had been used for Signal flare casings,any idears.
Thanks
J.S