do the pads you have to replace

Thanks for asking! You will need to replace the TENS pads after multiple uses since they use a gel overlay and lose their stickiness after a while. You can find the replacement pads here: https://carex.com/products/accurelief-tens-unit-supply-kit

Is there a positive and negative labeled? They seem the same.

No, there is no label. The only thing that matters is that each electrode is placed near each other.

Is there a positive and negative labeled? They seem the same.

No, there is no label. The only thing that matters is that each electrode is placed near each other.

I have chronic achilles tendon issues...at the back of my ankle. Should the pads be placed on either side and what is the optimal setting?

Great question! Yes, the pads should be placed on both sides to allow the current to travel through the area in pain.

For your settings, studies have found setting your device to these levels to work best:

Pulse rate: 2-10 Hz
Pulse width: 120µs
Timing: 20-30 minutes,up to five times weekly

For more details, we highly recommend using our TENS therapy cheat sheet. We've taken numorous studies and advice from our team of experts to create an easy to read guide when using your device. It includes various techniques, settings, and pad placement. You can find it here: https://cdn.shopify.com/s/files/1/0240/6504/8681/files/TENS_Therapy_Cheat_Sheet.pdf?v=1664221356 

Hope this helps!