The Ultimate Tool for Bold Transitions. When your design requires maximum leverage, our 4.0mm Brown Anodized Aluminum Bonsai Training Wire delivers the brute strength needed for major structural work. This extra-heavy gauge is the professional choice for guiding trunks and thick primary branches into dramatic new positions. Despite its incredible holding power, the aluminum is tempered for a "trouble-free" application, allowing you to manipulate heavy wood without the struggle of traditional copper. With 9.5 feet of high-tension wire, you have the foundation needed to turn a raw specimen into a masterpiece.