Doesn't replace a full set but we'll woth the money great to carry in your vehicle.OK . . . I was a little skeptical of these, as I've tried many "no slip" design sockets that it's not even funny. This design however, looked to be very different and I decided to give them a shot.WOW is all I can say! The rear brake lines on my truck need to be replaced, and none of the nuts would budge. My flare wrench quickly rounded off each and every stubborn nut, and open end wrenches with supposed no slip design also spun right around each nut. Last resort - I cut each metal brake line with a pipe cutter so I could slip on the Skil Secure Grip.The two nuts that connect via a junction block put up a fight, but the Secure Grip's internal grip ring came into play and they twisted right off. The nuts connecting to each brake wheel cylinder (drum brakes) put up a much greater fight. I had them in a vise and pulled like crazy on the wrench but they didn't budge. At this point, I wanted to see how tough these wrenches really were . . . so I slipped on a 2 foot "extension pipe" on the wrench. The little bugger is TOUGH, because each nut cracked open without slipping in the Secure Grip!I am beyond impressed and happy with these, and can't wait to put them to the test again!A lot of people are complaining about it not working for every size it says it is specified for but regardless of that fact it's worth the price all day. Also, people complaining about it feeling cheap because there's a little play... but I'm pretty sure that's just how they had to make it to ensure the mechanism wouldn't seize given that they've used 2 materials to make for a better grip. I think it's a great price for what you're getting. I wouldn't use it on everything but I'm definitely looking forward just struggling a little less next time I have something that's stripped.I bought these because I rounded off the bolt heads holding on the rear calipers on my car. The bolt locations are such that only a box end wrench can get too. Plus they were rusted so my 12pt wrenches instantly rounded them off. Took a chance with these (why not? They're only $13!) And was pleasantly surprised. The harder you pull, the better they grip. Was able to get the rounded bolts off pretty easily! I can't comment on the longevity of these wrenches, but I can say I was using the 13mm (second smallest) and was probably putting over 60 ft-lbs on it and it felt like it could take more. Very impressed. Best $13 I've ever spent.I'm a weekend mechanic. I saw the ad on television for these wrenches and decided I needed to have them. Many a time I have found myself wondering how I'm going to get a rounded out fastener loose. Many a time my only option was to use vise grips. These wrenched are unique that they apply pressure to the flats of a nut or bolt, not the points as conventional wrenches do. If the nut or bolt you are trying to remove or install is rounded out a conventional wrench may not work (and just spin) and you could be up the creek to finish a repair job. These wrenches may just work well enough to get the damaged fastener loose and out that you can replace it.Gave these as a Christmas gift to my father-in-law, who loves gadget tools. This set of wrenches has taken up residence in his toolbox, and he couldn't be more pleased. They have a good heft to them, and really work well to grip nuts securely. They do need a bit of space to get in there (no angles to the heads) so they probably won't work in tight spaces, but otherwise they're a neat tool that really reduces the weight in his toolbox compared to the multiple wrenches he used to carry.Though it didn't serve the purpose I bought it for. They helped in another not so tough situation. Not a bad set of wrenches to have around, but seem kind of cheaply made, did have one bend on another use. Just don't expect too much from them all in all in my opinion.This are good if you not sure if the bolt is standar or metric other than that it doesn't help much as it only goes from standar to metric not two standar sizes or metric.