High quality TeWa (pronounced 'Tay-vah' ) brand needles are bi-metallic - a stainless steel shaft and a traditional copper-wound loop handle. Needle tips are ground by automated machines, thereby ensuring perfect needle tip consistency. Practitioners have noted that bi-metallic needles made of copper/stainless steel have a stronger energetic effect than those made up of metals with similar energetics (i.e. stainless steel paired with aluminum or chrome). The yin/yang nature of different metals creates an electron transfer, giving the needles an enhanced energy. In sizes from .05 mm to 125mm (4" ) in length and .16 to .35 mm in thickness, coated TeWa needles are available now. Coated needles have a micro-layer of bio-inert FDA-approved silicone which reduces friction on insertion, enabling practitioners to reach target depth AND minimize patient discomfort. Each TeWa needle 40mm and longer is packaged in a Safe-T Sleeve , the worlds first two-part guide tube. The Safe-T-Sleeve is the latest innovation in needle delivery, providing increased patient comfort and clean needle assurance.