The two most commonly used types are copper and aluminum. It is not the same wire you would find in a home hardware department.
Aluminum is sized using the metric system, starting with 1.0 (the smallest). It is most frequently used on deciduous and fast growing trees you need to wire often. The most common sizes for beginners are 1.0, 1.2, 1.5, 1.8, 2.0, 2.5 and 3.
Copper is measured by gauge, the lower the number the thicker the wire. Copper wire must be annealed, and will “harden” once bent making it great to use for slower growing trees like conifers. Take care in transporting copper wire. The more it gets bumped around, the stiffer and harder to work with it will become.

• ALUMINUM WIRE:
• Eastern Leaf – https://www.easternleaf.com/
• House of Bonsai – https://www.houseofbonsai.com
• Stone Lantern – https://www.stonelantern.com/
• COPPER WIRE:
• Peter Tea – https://www.ptbonsai.com/copper-wire
• Mirai (Oregon) – http://www.bonsaimirai.com
• ALUMINUM WIRE CADDY:
• Bonsai Caddy – http://www.bonsaiwirecaddy.com/
• Greenwood Bonsai – https://www.bonsai.co.uk
• COPPER WIRE CADDY:
• Adams Bonsai – http://www.adamsbonsai.com
• Peter Tea Tip – Use a round jumper cable Bag!