The kerosang rantai/kerongsang brooch is a set of 3 brooches used by the Peranakan Straits Chinese ‘Nyonyas’ to fasten kebaya/baju panjang. Kebaya top has no button. Kerosang consists of three identical shapes and designs connected with chains. 
 
Butterfly dimension:
H: 2.5cm & W: 3.5cm