Great quality. Easy to use. Works great! Highly recommend to anyone needing to removing superficial stains. It allows the acid the flow directly on the stain slowly removing the surface layers. Took 5 minutes to remove 2 baseball sized stains on a pebble tech pool. These were light stains but this tool works awesome on heave stains Ex: bottle caps, nails, Bobby pins that get in the pool and leave a heavy rust stain.