Very conservative ESV:
1Likewise, wives,(A) be subject to your own husbands, so that(B) even if some do not obey the word,(C) they may be won without a word by the conduct of their wives, 2when they see your(D) respectful and pure conduct. 3(E) Do not let your adorning be external—the braiding of hair and the putting on of gold jewelry, or the clothing you wear— 4but let your adorning be(F) the hidden person of the heart with the imperishable beauty of a gentle and quiet spirit, which in God’s sight is very precious.
Can't get any more clear than this
Not material things (particular to what they were probably wearing and related to -- women had jewelry, did their hair and concerned themselves with clothing), but the "hidden person of the heart."