Various types are available, but the main distinction is between those with metal handles (wound with wire) and those with plastic handles. For most purposes Japanese Seirin needles, with plastic handles, are the best of those currently available, but metal handles are required if you wish to use electrical stimulation. The ‘business part’ of the needles is made of steel; there is no advantage in using needles made of gold or silver.
Needles vary in length and thickness. The most generally useful needles are 30 mm (1 inch) long, but it is also necessary to have some 50 mm (2 inch) needles as well and at times shorter (15 mm, 1/2 inch) needles are required. The common thicknesses for the 30 mm needles are 0.3 and 0.5 mm; 0.3 are less painful for the patient but require a little more skill from the acupuncturist. The short needles are 0.23 or 0.2 mm and the long ones 0.5.
The needles should be individually packed, otherwise many will be wasted. It is possible to buy them with ‘introducers’; these are plastic tubes which are placed against the skin, the needle being tapped with the finger to insert it. Some people like these, but others find them annoying and discard them.