**Product Specifications:**
**Brand:** uni
**Series:** Mitsubishi Signo RT
**Product Name:** UNI Classic Retractable Gel Pen
**Features:** Rich color options, exquisite pen tip, rubber grip, smooth writing
**Origin:** Made in Japan
**Product Attributes:** O, UMN-105/138/138S, 0.38/0.5mm
**Color Options:** Multiple colors available
**Model Numbers:** 0.38mm and 0.5mm
**Special Features:** Dual-ball design to prevent ink leakage, stable rotation of the pen tip, vibrant and colorful ink, smooth writing experience
**Ink Type:** High-tech pigment ink, waterproof, lightfast, non-fading, non-smudging, stable writing, smooth ink flow
**Pen Tip Sizes:** 0.38mm for blue, black, and red ink; 0.5mm for other colors
**Ink Colors:** Blue, black, red, light blue, pink, orange, purple
**Grip:** Comfortable rubber grip for long writing sessions
**Refillable:** Transparent pen barrel for easy ink refill, eco-friendly and cost-effective
**Limited Edition:** Vibrant polka dot design, suitable for a cute and fresh style
**Hidden Patterns:** Explore hidden patterns on select designs
**Size:** 140mm length, 10.5mm diameter, writing tip sizes 0.38mm/0.5mm
**Color Variants:** Black, blue-black, blue, sky blue, pink, red, orange, purple
**Ink Variants:** Blue, black, red, pink with black ink; rose red with black ink; purple with black ink
(Note: The specifications include detailed information about the uni Mitsubishi Signo RT series gel pens, highlighting their design, features, ink options, and special characteristics.)
