Based on our own experience, this hex tool set is a great addition to any industrial and scientific toolkit. the metric sizes are clearly marked on each key, making it easy to find the right size for the job. The durable design of each hex key ensures that they won't bend or break under pressure making them a reliable tool for repeated use... The only downside is that the keys may not fit into tighter spaces compared to other hex tool sets. Overall, a great investment for any professional looking for high-quality hex keys..