United Abrasives-SAIT 20063 Type 27 4-1/2-Inch x 1/4-Inch x 7/8-Inch Grade A24R Long Life Depressed Center Grinding Wheels, 25-Pack Long life for fewer wheel changes General purpose grinding on ferrous metals, including iron, steel and welds Internally reinforced with the highest quality fiberglass for maximum safety High stock removal for tough applications <span class="a-text-bold">Long-lasting and safe.</span> We only use premium grains so you can be sure you&#039;re purchasing abrasives that hold up over time and are safe for use. <span class="a-text-bold">High-quality backing</span>. We use premium heavy duty fiberglass reinforcement to ensure that our abrasives meet your needs. <span class="a-text-bold">Made in the USA.</span> Products manufactured right here at our facilities in Connecticut and Florida.