This nut and washer assortment from Westinghouse has been a lifesaver for our HVAC equipment repairs. Based on our own experience we found this product to be an essential addition to our toolkit .the assortment is organized and contains various sizes that fit most jobs. It is made of high-quality materials and can withstand tough industrial and scientific conditions. However, SOME of the nuts may be too small for larger HVAC units. Overall, we highly recommend this product for anyone in the material handling industry..