Interpens is an online shop specializing in fountain pens, writing instruments, accessories, and vintage classics. Its catalogue spans established brands such as Montblanc, Pelikan, Parker, Kaweco, Waterman, Aurora, Visconti, and Graf von Faber-Castell, alongside lesser-known and historical makers. Shoppers can browse fountain pens, rollerballs, ballpoint pens, pencils, and writing sets, with products that include both contemporary offerings and collectible vintage models.

The store also sells pen accessories, cases, ink bottles, books, and desk and office items, as well as replacement nibs and parts for selected brands. Its featured and popular listings showcase individual pens and desk accessories, with prices displayed in euros or US dollars. Interpens highlights new arrivals, special offers, and customer wish lists, and provides account registration and order tracking.

The shop also lists repair services, suggesting support for maintaining writing instruments, and provides information on its terms, returns, privacy, and contact details. With a broad selection organized by instrument type and brand, Interpens serves enthusiasts and collectors seeking distinctive writing tools and related accessories