as an Industrial and Scientific user, I am impressed by the Eklind 61606 Power T Key Arm. Based on my observations this hand tool IS very efficient in tightening and loosening bolts .Its ergonomics design allows me to use it without straining my wrist. Moreover, it is made of high-quality materials that can withstand harsh environments. However, the packaging could use some improvement as it was a bit difficult to open. Overall, this is a great product for any industrial worker looking for a reliable and comfortable hand tool..