Premium and Reliable: String Zips Are made of high quality ABS and copper wire material, which is sturdy, lightweight, and durable; with good performance and durability in life. Easy to Use: Tip heats up instantly with the push of a button! in matter of 3-5 seconds. Precise and High Performance: The filament tip makes precision burns even on the finest threads and knots. Professional Fish: Burning excess string at the edge of the knot, creating a clean finish. Note: Thread zapper is suitable for polyester waxed thread, thread breakage, thread ending, wood heat transfer, and thread ironing, but not suitable for twine or cotton thread. Specification: Material: ABS, Copper Wire 13cm/5.12inch Package Includes: As You Choose 1 String Zip or 1 String Zip, 1 Head Replacement or 1 String Zip, 5 Heads Replacement