Specifications: Pen Body Material: Aluminum alloy Nib: nylon Nib type：BT-2.0/3.0/4.0/5.0 (can be choosed ) Pen length: 168MM Pen weight:16g Holder material：Aluminum alloy, ABS Holder weight：26g Holder size：56*49*22mm Holder color :Black/Red (can be choosed ) Features: Four colors are available, stable holding, not easy to corrode, convenient and fast Replaceable nib: Rotary grip and spring combined with pressure-mounted nib, easy and convenient to operate Model window: After replacing the pen head, the knob and the end of the pen identify the pen head model, which is convenient and easy to understand Fine painting: The pen end is hollowed out to make the pen body lean forward, making it easier for fine work Not easy to fade Long life and durable Simple and convenient operation Nib replacement method; 1. Take out the spring after the pen holder is separated 2. Put the replacement pen into the pen compartment 3. Add spring 4. Tighten the pen grip and the pen barrel Notice ·Do not knock or drop this product, otherwise it will cause damage and make it unusable. ·Please clean the tip of the pen after use to prolong the service life.