I have heard this referred to as an old fashioned audiotape recorder, and a Reel to Reel Audio Tape Recorder. Not sure which is the proper name, but hopefully you know what they are.
Plated and enamel cufflinks.
Dimensions (LxWxH): 23mm x 23mm x 4mm (approx.)
Weight per cufflink: approx. 9.34g (average)
Size = x mm (W x H)