Do they attach onto the main light, or is it mounted on the helmet?

Am toying with either getting a Diablo / Axis with the Tap control thing so i can swap between hi and low, or a joystick with a piggy back battery and just run this on high all the time to give me around 3 hrs burn time,

If the piggy back battery is faffy to attach i may not want it as i’d like a light that can just be quickly clipped on / off the helmet.

I ordered a triple from Smudge at mtb batteries. About half the price and he let’s you choose how long the cable is. I went for a metre so it goes in my jersey pocket.