"I have worked in engineering on maintenace for over 38yrs and I've used all makes of Hex keys including snapon and these are without doubt the best hex key I've ever used. They fit great don't twist or slip. In time the sleeving does become damaged but this does not effect the performance. I've even used a 300mm long tube on them to increase leverage and they have not bent or twisted. Anyone looking for a excellent hex key should look no further."