The TENS unit is useful too, it just works differently to the the clark and beck zappers. Check out Geritol's posts for how he used the TENS to herd worms from his neck and head area. It does make them move, there is no doubt about that - it worked for me keeping them out of certain areas when they became very painful. Geritol also claimed that he was able to kill them with his TENS. Regarding Parazapper's post, I have a few of his models and they are great, as well as a bob beck style zapper which I bought from an Australian supplier. The Hulda Clark e inpired Zapper works in a different way to the Beck. The Beck zapper purifies the blood using two metal rods covered in cloth attached to you wrist vein; the other type works across the body with hand held copper pipes. All devices are very good to have in your arsenal.
Here are links to the Beck zapper and magnetic pulser, as well as parazapper