1、High precision, stable steering and good performance. 2、Sleeve diameter: inner diameter 6mm/8mm, outer diameter 12mm. 3、Made of high quality copper and graphite materials for long-term use. 4、Suitable for Ultimaker2 UM3 3D printers. 5、The design is exquisite and easy to use. Small size, convenient to carry. Features: 1. High precision, stable steering and good performance. 2. Sleeve diameter: inner diameter 6mm/8mm, outer diameter 12mm. 3. Made of high quality copper and graphite materials for long-term use. 4. Suitable for Ultimaker2 UM3 3D printers. 5. The design is exquisite and easy to use. Small size, convenient to carry. Specification: Type: DIY accessories Material: Copper + Graphite Color: Yellow Size: approx. 6*12*35mm/ 0.24* 0.47* 1.38inch, 8*12*35mm/ 0.31* 0.47* 1.38inch (optional) Weight: approx. 64.5g Package list: 4 * Graphite Copper Sleeves