Proform CO3.0S Oval Straight Cut 70/30 Blend 3 Paint Brush
Proform probably has created the widest variety of oval paint brushes of anyone on the market. While their true innovation is in creating angled oval brushes, they also have straight cut oval paint brushes as well. This 70/30 blend brush is designed for using with all types of paints, but I think it will work best with latex and acrylic paints. I've selected the 3-inch brush here, but it comes in sizes ranging from 2 to 3.5 inches. Like the angled brushes, they've put quality into every detail of this brush, especially the attachment of the bristles to the handle.