This cleverly minimalistic double-sided wooden nib holder can be used with a wide range of nibs. One end fits G, spoon, Japanese, and school nibs, and the other side fits round maru (mapping) nibs. A list of compatible nibs can be found under Recommended Refills/Parts. With a nib installed on each end, you can instantly swap between different nib types. Use one nib for expressive strokes and the other for fine details. The holder's hexagonal design is comfortable to hold and prevents it from rolling away.
Also pictured: Deleter Manga Ink Black 6