Voltage: 4.2V Speed: 5000–18000 RPM Clamping Diameter: 2.35 mm (compatible with all 2.35 mm grinding heads, drills, etc.) Wireless Electric Grinder Pen: Features a built-in rechargeable lithium battery for cordless operation. Three Speed Settings: Adjustable output from 5000 to 18000 RPM. Three-speed control allows precise adaptation to different tasks. Dual Power Mode: Can be used while charging via USB power supply. Package Includes: 1 × Engraving Pen 1 × USB Charging Cable 2 × Drill Bits 3 × Saw Blades 30 × Assorted Bits 1 × Tungsten Steel Bit 1 × Connecting Rod Note: 1. Fully charge before first use. 2. Not intended for heavy-duty carving, punching, cutting, or grinding. 3. Operational noise and heat are normal during use. Color: As shown in image Material: Metal Package Contents: 1 × Engraving Machine Light reflection and display variations may cause slight color differences between the image and the actual product. Measurement tolerance: ±1–3 cm.