The etcher units are really just transformers that I had laying around from old cordless phones and electrical devices that I cut the connectors off of and put an alligator clip on one wire for the ground and a little home made handpiece on the other wire. For the handpiece I took a 1/2" wooden dowel and drilled a 1/8" hole in one end about an inch deep, then I took one of the wires and wrapped it around a screw that fit the 1/8" hole. Put a 1/2" washer on the screw and screw it into the hole, that makes the contact end for etching. Then I secured the wire to the dowel by wrapping it with electrical tape....For the deep etch I believe that I used a 800milliamp ac to dc transformer, and for the the one that leaves the black mark I think that it was a 1000milliamp ac transformer. Don't get too hung up on the milliamps I just used what I had on hand and it worked great. You may have to experiment with the wires to see which one should be the ground and which one is the lead.. here are some directions that I typed up to go with the unit..