Body Clock Babycare TENS Elle Pain Relief During Labour

Does it require batteries? How many and how long would they last on average?

Do you get vibrations on all 4 electrodes or just the ones attached to the black leads?

When you press the boost button for a contraction, do you have to keep your finger pressed down on the button throughout the contraction?

I used this tens machine during my last labor. Im looking into new pads. Does anyone knpw if thats all i need? Thank you