This is a very unique and vintage sterling silver "Oil Derrick" in shadowbox cufflinks by F & S (Fenwick & Sailors). 

Weight is 16.8 grams.

Size: about 3/4 inch (2 cm) square and 7/8 inch (2.2 cm) tall when the back is leveled.

Marking is "OIL DERRICK © F & S STERLING" on the back of each cufflink.

Condition is previously owned but excellent with normal age tarnish as shown! 

A dime is placed for size reference and not included.