【Unused】 21_21 DESIGN SIGHT Original Water-Based Sign Pen by Pentel This is a sign pen exclusive to 21_21 DESIGN SIGHT. It's an original item featuring the familiar Pentel sign pen body, colored in the same blue as the 21_21 DESIGN SIGHT symbol, the "Product Logo." The ink color is sky blue (light blue). It is believed to be designed by Naoto Fukasawa. It has been opened but has been stored unused in a dark place.