I needed to shorten a new chain and wanted to try myself vs. taking my bike to a shop. This tool did the trick for me, but it wasn't all easy.

I'm not an expert bike mechanic, so maybe I just need some practice, but a couple of key takeaways from my use (that may be me, may be the tool, or may just be the way it goes) ...

- I saw enough videos that explained NOT to push the pin all the way out of the final outer link (to make it easier to push the pin back in again afterwards). Since you can't see the pin coming out, it was difficult to tell how far to keep turning. The first time, the pin came out completely. No complete obstacle in the end, it just made it harder to get the chain back together after removing the links.

- I noticed after removing the first pin that the metal "guides" on the device had actually bent due to the force of driving the pin out. I was careful to try and center the pin pusher and so I don't believe I was ever just pushing the whole link, but I was surprised to see the metal bend. Luckily, that softness also meant it was easy to bend back using a flat head screwdriver, but overall I would expect this part of the device to be heat treated for strength vs. flexibility.

- The (minimal) instructions show you how to break the chain, but not to re-join it. Again, the internet abounds with tutorials, but it was a little tricky (especially since I had to try and get the pin to hold in after it had come completely out in step 1!).

It got the job done, and I think next time I would have a slightly easier time, but the softness of the metal and lack of instructions cause me to not give it a to rating.

Oumer's Chain tool ---- I haven't used it extensively and I admit that I bought this tool without reading all the reviews. So, from my limited experience with this tool I feel that it does the job of removing chain pins easily and efficiently. As others mentioned there were no instructions with the tool but experience with other chain break tools kept me from making mistakes that resulted in bent chain supports and broken push pins. The hollow screw (opposite the pin) needs to be screwed in to support the chain while you are twisting the handle and applying pressure to push out the pin. The hollow end will catch the pin if it is removed completely.

BTW - when putting chain back together purchase new replacement pins, Yes, you can save a few $$ by using the old pin. If you completely remove the pin it is tough to align the links/holes to get the old pin in correctly. It can be done but may cause the chain to bind or seize. Replacement pins have a long slightly smaller diameter section that you insert into the chain links. This section guides the slightly larger diameter chain link pin into the holes. When the link pin is fully inserted remove the chain from the tool and use a pliers to snap off the guide section of the pin. Search Amazon for Bike chain replacement pins - know the brand of chain, number of gears in your rear cassette, and make some measurements of the chain pin length and it's diameter. this link is an example: "Shimano 10-Speed Replacement Chain Pins"

If, in the future, you want to remove your chain for cleaning etc use a replacement link similar to: "YDZN Bicycle Chain Link Connector, 11 Speed Quick Master Link Joint Clip (2 Pcs,Silver)" Park tool sells a "pliers" for use when installing and removing this type of link. Again, these links are not "generic" so you'll need to know the chain you are using the replacement link in. Use of these links make it easy to remove the chain for cleaning or repair.

PROs -- fits my hand comfortably and the large handle is easy to twist. in and out. The hollow screw captures the pushed out pin and supports the chain while working on it. An extra pin included in the handle along with the wire chain hook
CONs - as others mentioned it is a bit large to be carrying "just in case" you need a major chain overhaul while on the trail or road. It can stay in my tool box - it fits nicely in there.

Question I have: looking at the assortment of chain tools on Amazon why are there so many tools that look just like the Oumer's tool but have different names. They are all in about the same price range.. Strange....... :-)

I have not received any support or compensation from Oumer's or from any company selling replacement pins or replacement links. Why give it only 4 stars? I reserve 5 stars for something that really blows my socks off. This is a good tool and "I like it"

If, after using this tool more I have information to add to this review I'll do that. Till then, enjoy your days on the trail.

So I used it once and have some initial thoughts. For the price it definitely feels good and I like the spare pin it comes with and the tool to take slack off the chain while using it. The main issue I have is that the pin doesn't line up perfectly with my link when trying to separate it so I have to get the chain link sitting sort of weird in the device for it to be a perfect alignment, but it's not difficult to do. And unless I just can't figure it out, I wish it came with an easy way to get the chain link pin back in if you completely need to remove it. My old tool had a way to do it, wish this one did, and it doesn't come with any instructions and I cannot seem to find any online so I don't think it has that ability as far as I can tell.

Chain mount guides bent on first use. I ended up spending 3x more to get a name brand chain tool. Wish I didn't need to spend so much, but the name brand tool working perfectly.

This is the first chain tool I have ever used, and I have used it exactly once. I was able to quickly determine how to use it and successfully replaced the chain on my bike. I am impressed with the ease of use and the speed at which I accomplished the task. I cannot speak to the long term durability or the relative quality compared to other similar tools. Obviously, I am not running a professional bike shop and will likely use this tool once a year at the most, but for the price I paid, it was well worth it. I can see none of the flaws mentioned in reviews of other tools and I cannot see how this tool, when properly used, would experience enough stress to damage it. As with all my reviews, I will return and update with further reports if and when my opinion changes.