This is almost certainly a Lewis Gun Magazine Pouch but might have taken those circular 'Tommy Gun' Magazines. You purists out there will know!!!!

This item is totally MINT and without a blemish.
"Quartermaster's Comment":- On the inside of the pouch it is clearly stamped M . EC followed by what looks like an 8 then the date 1940. Further up and to one side is stamped in black also an Arrow over what looks like 58 over the standard "U" for Union of South Africa. It weighs in at around 300 grams and measures around 22 cms across and 22 cms from top to bottom. It is around 9 cms wide......so could well have taken two magazines? This item is in superb order after almost 70 years.......which is more than you can say for the Quartermaster!!!!!!