Spotted this n a 1966 Analog magazine serial called 'Amazon Planet' by Mack Reynolds. Basically they look like standard 'gypsy style' golden coloured bracelets or bangles (I'm going by the illustration (Picture linked below), which shows them being worn three to an arm.), actually they are weighted and can be used as a sap or as the thread title suggests...
If this appears in the Classic or Gaslight periods they'd probably be apparel for someone playing a female 'Bohemian' character. I'll need some help working out the stats.
https://app.box.com/s/2hiwv0z90qjsw0ddcnaai74xalx55vsf
'Brass Knuckle' Bracelets
"If you do good, you'll live forever, if you do bad, you'll die hearing a single note for I am the one true sound...", Fragment found in a cult hideout.