capacitor values

I want to replace capacitors in some '70s speakers that read 12MFD 50 wv non-polar.
It's the 50 wv (volts) that I'm having trouble finding on line. Lowest I can find 100v.
Also A white ceramic rectangular that reads: C w 5 10 (some kind of mark) K 3-A.
Help me if you can,please. So I can get these ordered
Is this VIS 10W 1,0: VISATON ceramic resistor at reichelt elektronik
closer? You should be able to test the resistor's value with a Digital Multi-Meter. You do HAVE a DMM? If not Bwell get one PDQ! Nobody should poke around electrical kit without one.

The capacitor advice is sound. You might read that FOIL capacitors are audibly superior to electrolytics? Whilst this is true at the very limit of audio cork snifferey, DO NOT be tempted to replace the caps with foil types. It will screw the HF response mightily.