This item worked as intended for both presta and regular shader valvesI had purchased some of that "slime" to help puncture proof my bike tires, but the core removal tool that came with it proved useless after one application (the second stem literally tore it up). I bought this one with one day shipping and the instant I held that metallic tool, I knew it was a keeper. I finally finished "sliming" my bike tires within the hour. Worth its weight in whatever metal it is.It’s a great tool. Used almost daily no complaints except one. I’d like if it was magneticIt's small enough to fit into a patch kit, and it works great for all your valve-core screwing and unscrewing needs.So...why would anyone want to screw or unscrew a bicycle tube valve core, anyway? My comments below are all about Presta valves as I haven't had Schrader in years and am not qualified to comment on them.First of all, this gadget is only useful to you if you use Presta tubes, such as works good but in my opinion, it's way overpriced!my bicycleMy bike has Presta valves, my wife's has Schraders. Having one small tool that enables me to pull the valves off either bike, shoot in some Slime tube sealant, replace the valve, and pump up, is a godsend when we get flats on a remote 25-mile ride.Funciona perfectoI would suggest that it is a little overpriced for what it is - hence 3 stars instead of 5. A good quality product. CNC machined from 6061 aluminium. Far better than a cast aluminium one. Does what it is designed to do.Although it did fit my shrader valve, I didn't buy this for that purpose. It doesn't fit *ALL* presta valves though. I've had to fork out for proper tubeless valves because this is the 2nd core remover that didn't fit my presta valves! so check before you buy.Having had a few annoying punctures in my tubed tyres, and fed up off having to repair out on ride, decided to use tyre sealant in the inner tube, rather than going tubeless. Removed valve easily enough from old repaired tube with spanner, but as you have to top up the sealant occassionally, and it is another bike tool (can't seem to resist collecting them) decided to buy this. Works well, simply drop over valve, twist and remove, no problem, and reinstate valve on completion. Worth buying.Feels solid in hand, much better than cheaper alternatives. I used this when i converted to tubeless on my gravel bike. Made the job much easier.Buy cheap buy twice - This is a good optionPurchased to replace the core on my new tubeless tyre setup. Works very well.