Staalmeester is a fourth-generation Dutch family business that makes specialty paintbrushes. Their offerings are unusual, to say the least.

This Round Brush 6121 was designed to paint narrow items like window frames, edges and profiles. The round bristle arrangement holds more paint than a flat one.

The Round Brush 3600 offers the same design in larger diameter sizes.

This Bent Fitch Brush 0304 is for getting into the corners of door frames and window frames.

The Façade Brush 4210 is designed for painting hard-to-reach areas.

Ditto the Façade Brush 6110, the same design with a longer handle.

And this similar Radiator Brush 0136, as the name suggests, is specifically sized to paint behind radiators.

You can see more of their offerings here.