At the price I wasn't expecting too much, but I only had it (3/8 to 1/2) out of the packet for 5 minutes (probably less) before it sheared off. I hadn't even started to put on much pressure, so to avoid any nasty scraped knuckles in the future, I threw the others in the bin. I'm not sure what these are made of (toffee, perhaps?), but are certainly not "Heavy Duty", as stated on the packaging. Unless you are undoing nuts that are little more than finger tight, avoid these cheap, but also very nasty adaptors.