Mail armour
Quran corpus data
The root sīn bā ghayn (س ب غ) occurs twice in the Quran: (34:11) and (31:20)
In The Quran
(34:11) That you may make mail armour (Arab. سَابِغَاتٍ, sābighātin) that fit perfectly, and work righteousness. For I am Seer of what you do.
(31:20) Did you not see that God has committed in your service everything in the heavens and the earth, and He has showered (Arab. وَأَسْبَغَ, wa-asbagha) you with His blessings, both apparent and hidden? Yet from the people are some who argue about God without knowledge, without guidance, and without an enlightening book.
David, Iron Age and Mail armour
(34:10-11) We granted David blessings from Us: "O mountains, glorify with him, as well as the birds." We softened the iron for him. That you may make mail armour that fit perfectly, and work righteousness. For I am Seer of what you do.
"As its name suggests, Iron Age technology is characterized by the production of tools and weaponry by ferrous metallurgy (ironworking), more specifically from carbon steel." - citation from the Wikipedia article Iron Age
