I purchased this pump to seat tubeless tires on my gravel bike. I soon found out that the chuck included with the pump does not thread on to a valve stem with the core removed. My experience has been that when reinstalling a tubeless tire that has already been used for a while, you almost always have to remove the valve core to get enough air flow to seat the bead. Once I got the Lezyne tubeless chuck to use with this pump that process has been easy. But I should not have had to buy the tubeless chuck separately.
As others have said, this tool is beautifully crafted. However, the description misses one important detail: the chain breaker tool brakes chains and connects chains, but it does not do the fine-tuned loosening that a full chain breaker does. I bought this tool because I thought I could get a good two-for-one; now I'll probably need to get a regular chain breaker. I also contacted Lezyne's customer service, and they responded flatly that this is not a full chain breaker tool.
This pump works very nicely, is solid and appears to be in all respects well built. It efficiently delivers a good volume of air per pump stroke with less resistance than many others. There is a little bit of a learning curve in screwing the threaded nozzle onto a Presta valve but once you get the hang of it, it is pretty simple. It does take a bit more time to affix and disconnect the nozzle from the valve stem than is the case with pumps that attach their nozzle with a locking lever, but you are talking seconds, not minutes. On the other hand, you will never bend or dislodge the little pin inside the end of a Presta valve with this pump.
This year Ive suffered 4 flats so far.. and of course when riding in a group we get them too.. Ive used the cheaper inflator head before and its a hit and miss, difficult to control. With this gadget, you get to inflate to your option.. slow or fast. One mistake I had was I forgot to close the valve after I used it so when you put the CO2 it spurted out and generally wasted half of it. Other than that, it was easy to use.