[167] Now at that time the group-of-six bhikkhus wore buttons of high and low kinds — made of gold, made of silver. People looked down upon them, criticized them, and spread it about, saying, "… like householders who enjoy sensual pleasures …" … They reported this matter to the Blessed One. … "Bhikkhus, buttons of high and low kinds are not to be worn; whoever should wear one commits an offence of wrong-doing (dukkaṭa). I allow, bhikkhus, a button made of bone, made of ivory, made of horn, made of reed, made of bamboo, made of wood, made of lac, made of fruit, made of metal, made of conch-shell, made of thread."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.