See for glas tips also
http://home.hetnet.nl/~kroese/index.html
subpage "insemination"
The text is in Dutch. sorry
Ik make the tips myself. There are 2 fotos of a coil that i made myself.
The wire i use is frame wire stainless steel. Diameter 4 mm. keep the
windings compact. 1 cm length. 12v battery charger works perfectly.
success H. Kroese Holland.