I found these “purple” stripping discs were durable and worked well for a wide variety of applications.They remove rust and paint from metal with ease, they also work great for smoothing out light surface defects on metal surfaces and for polishing stainless steel. These are mildly abrasive, so depending on your application you may need additional surface prep.I found that “purple” discs of this type are a bit more aggressive and last longer than the “blue” discs, I have not tried the “black” variety, so I can’t comment on those.At the time of my order, the set of five discs was priced under $22, which seems like a reasonable price for the quality and durability these offer.One important note: These are FIVE INCH DIAMETER discs requiring a 7/8” arbor. As such, they may not fit all 4.5” angle grinders.I found these work best and last longest when used with a variable speed grinder set around 70%, as they are less likely to melt. (When run at 10,000 RPM, if pressed hard, they have a tendency to melt, as do all non-abrasive type wheels. In my experience, running these at a lower speed reduces heat and provides superior results.) I am pleased with these discs and have purchased more for a stainless-steel sculpture project I am working on. They have been beneficial in cleaning up the stainless and blending mild scratches prior to graining. I’m also using these to strip paint off metal for a tractor I am restoring.Bottom line: A versatile, cost effective, mildly abrasive disc that is a huge timer saver. Definitely worth having in your shop.