These appear to be vintage Siam Nielloware sterling silver cufflinks depicting the goddess Mekkala. 

• Material: Crafted from sterling silver with a distinctive black niello enamel finish.

• Design: Feature a traditional Thai design, often depicting the goddess of lightning or a dancer.

• Era/Origin: Likely produced in Siam (modern-day Thailand) during the mid-20th century.

• Value: Similar pairs have recently sold for approximately $18 to $40 depending on condition