I recently came across 2 styles of these small metal boxes. With some research I have discovered that they are some sort of sniper spare part tins. They are marked as follows...
CM 98 MK. 1 1944 CNFP
The second one is the same, with the exception of the 1944 being a 1945. They also both have a sea broad arrow stamped on them. Any assistance in further identification or explanation would be greatly appreciated!