I am attempting to construct a transcranial direct current stimulator. I want to use an iontopherisis delivery device called Activadose II to deliver the direct current. Does anyone know what exact accessories could be paired with this device to deliver transcranial direct current stimulation?

You might want to post this question on the RSD forum:

This thread specifically is about your subject:
http://neurotalk.psychcentral.com/thread160980.html

Thank you for the tip. It does seem like a better place for the question.

The Activadose II is a fine device and is easy to use, but the unsupervised home use is potentially counterproductive and dangerous.

You need:

TENS wires
2 x pin to banana adaptors
2 x 2" by 2" sponge electrodes (you can get Amrex brand)

Putting it together is really simple. You just plug the wire to the Activadose, put one adaptor on each end of the wire, and then the other end of each adaptor will fit into the sponge electrode pocket.

If you search "transcranial technologies" they have a downloadable document that will tell you how to position the electrodes.

The machine ups the current very very slowly, so it is quite safe. If anything strange starts happening, you just ramp down the current manually.

Best of luck.