I wanted a small brush to apply soldering flux to circuits, but I didn't want to clean it every time I used it and I didn't want to create a ton of expensive waste, so I modeled this brush. It uses less than a gram of material and prints in under a minute. The bristles are 0.8mm wide and 0.4mm tall, designed to be printed with a 0.4mm nozzle and 0.2mm layer height. I use PLA and it works great.