- Japanese-made tip replacements for Wren Writing Pens - Produces smooth, consistent ink flow - Easy to replace for easy pen maintenance - Comes in a convenient pack of three Keep your writing pen in top condition with the Tom’s Studio Wren Writing Pen Tip Replacements. These durable, Japanese-made tips are the perfect sustainable solution to your worn-down writing pen. Once you are ready to swap out the tip, simply unscrew and replace. Extend the life of your pen, keeping every mark crisp and smooth with these durable writing tips.