Each brush is designed for a specific use, to clean parts that need heavy duty scrubbing, paint, rust, etc. Great set for detailing, shower door tracks, stove tops, tubs, sinks, grout, small engine parts and copper tubing, flaking paint, dirt and scale, surface cleaning, rust, paint & varnish removal. The bristles are smooth and deep, and gets all the way down into the nooks & crannies in areas that require a narrow face, without breaking. Extra cluster of bristles that helps you reach every corner and crevice, suitable for cleaning tight areas, seams, threads, and soldered joints that require a narrow face. Made of plastic for durability and to resist cracking, warping growth, bent for a secure grip and for knuckle protection.