This is a lovely unisex piece of motor sport.  Quite the industrial look!  It's an aluminum bearing cage with steel bearings placed in every second track of the cage weaved with genuine, soft, supple black leather.  There are six steel bearings in all.  Nice to wear as a cuff as it's narrower at the top and flares or widens slightly to the base, so fits your wrist and forearm nicely.  There is some scope to manipulate the metal to make wider or smaller as well and the suede backing makes it not only look smart, but a comfortable piece to wear too.
 
Measurements are:
65mm wide with room to widen or shorten
Weight is 55 grams - so easy on the arm too!