Thanks to my knowledge gained in practice I can say that these wrenches are the best investment you'll ever make .The ProGuard Finish ensures durability and maximum grip for THOSE tough to loosen bolts. The quality of these wrenches far surpasses other brands I've used in the past. One downside is the price point may be a bit high for some, but the value outweighs the cost. Highly recommend for any industrial and scientific applications..