Which is why they
banned them in the mid-80's actually.
Metal lunchboxes were banned in the early 1970s, as a result of a campaign of "concerned" Florida mothers against the steel lunchboxes. Children being children, were using the metal lunchboxes as a type of weapon, cases of permanent head injuries were being reported. The state of Florida banned the sales of metal lunchboxes in 1972, and other states soon followed in the banning. Box makers switched from metal boxes to softer plastic boxes. The last steel metal lunchbox was a Slyvester Stalone's Rambo model, produced by KST in 1985.
I did have one, when I was maybe 4 circa 1980:
But after that they were all plastic.
I converted to just carrying a backpack with me.
I carried my trapper keeper in my totally awesome JanSport backpack (also, new one required each semester!).