This is a tool for use in model assembly.
Adapted from the Tamiya website:
Dust be gone! This two-in-one Model Cleaning Brush has been carefully designed to help keep your display models looking their best. Its fibres not only remove dust and debris, but also static electricity, preventing dust build-up. The long fibres of the main brush make cleaning around large delicate parts easy, while the mini brush on the opposite end lets you get to those hard to reach areas. This brush is not just perfect for maintaining the look of plastic models, it's also great for cleaning other household items.