I agree with the core opinions I'm reading from a lot of other reviewers. I bought these for my two year old twin boys because they often have their train tracks tore up within minutes of being assembled. I was considering gluing the tracks down, but I read many parents who did that and regretted it because it made the train set a "static" toy when "dynamic" play is a big part of the fun of these wooden train sets.I'm still mixed on the glue idea, but I've decided against it and I thought I'd see how these did at keeping the tracks together.I'd view this product as a little bit as "riding the brakes" on active toddler. They can still tear the train tracks up, but it slows them down some and keeps the accidental tear downs from happening. So, it didn't quite hit my goals of hoping it could keep the tracks together despite active toddler intent to tear down, but it's not really the products fault. There just isn't a good way to keep a toddler who wants to tear train tracks down from doing so in a way that isn't fairly permanent as near as I can tell.Personally, I've mostly just resigned myself to rebuilding the tracks a lot. My boys have been getting better about keeping the tracks together a bit longer. So, presumably this will be less of an issue as they get a bit older and maybe this product will be better when the destruction is more accidental than deliberate. Not that my boys mind. "Oh no! A Crash!" is just as fun as the track staying together in their mind.Regardless, I think these are a good product that do help keep tracks together just be aware of what they do and don't do and set your expectations accordingly.These work very well. Other reviewers have noted they will stretch out, which I did not experience. If you push them over the tracks after the tracks are already interlocked, they may stretch out. If you want to keep them from stretching out all you have to do is put them fully over one end of track and then interlock the tracks and slide the clip over the joint.They work great, keep the tracks aligned in both directions, and work really well to keep the grooves lined up so the trains are less likely to derail.I think these are absolutely required for motorized trains, as they can fix joints that are not quite aligned. They also work great to make hills easier to stabilize on top of risers.42 clips is mostly enough to hit the critical points on two track sets combined, but they cannot interlock every single joint. In most cases there is no reason to have a clip at every joint.They don't work particularly well with riser blocks because of their shape, but you can use the clip to stabilize the joint and then put the riser away from the joint - it prevents the riser block from being the thing that is holding that joint together.These really reduce the frustration for a 2 year old and made it much more fun to play trains with her.We got a train table and set for our 18 month old and 3 year old and quickly realized we needed some way to secure the tracks. The whole set turned into a useless jumble immediately, and then sat unplayed with for weeks. I ordered these suretracks, and now all is great and the train set is getting lots of play.We have the melissa and doug wooden railway. If you want to secure all the pieces, get 4 packs of sure tracks, maybe 5. We got 4, and only a few pieces are unsecured.We did not receive the thomas stickers as advertised.I am shocked there are not more products out there to secure tracks. These were the only ones i found. While they dont look all that great, they work pretty well and dont get in the way of the trains.The clips were easy to put on and held the track sections together firmly. Once on the clips did not interfere with the grooves for the train wheels however they did get in the way of the bridge supports. The good news is that once clipped together the elevated track sections will stay up without support. I bought the clips for a Plan City layout. The clips will not fit on the roadway sections that are part of the Plan City set. They should make clips that fit the wider roadway sections and that would be great.We saw these at a local train show event and kicked ourselves afterwards for not buying them. So, I was really excited to find them on Amazon. Any parent who is sick and tired of constantly reassembling their child's wooden train set may jump at these clips. We certainly did. Since I had to pay for shipping, I ordered a couple boxes. My son tore into the packageing before we actually tried them out, so we couldn't return them.The parts of the track that typically fall apart and cause our son the most frustration are the bridge connections and the elevated tracks. These clips were useless for those problems because they have to snap securely around the seam between track pieces. Most bridge connections (at least in our sets) have part of the bridge in the way. They work for holding flat track pieces together, but those don't generally come apart anyway.We've had to find other solutions for the train table. For the loose track pieces that my son likes to assemble and reassemble, he changes the track layouts so often that the clips aren't needed anyway.I wish I hadn't spent the money on these.My sons are 3 and 1, and they tend to tear up the train tracks within 30 minutes of us putting it all together, so I was really hoping this would help us get more use out of his wooden train set, but all it really does is let them tear it apart into bigger sections. However, when my son wasn't actively trying to tear the set apart, they worked great at keeping the track together. If your children are older than mine and have more self-control, I'm sure they'll work great for you, but they are not a miracle item. We use a Kidkraft wooden train set and table, and they fit the pieces just fine.Perfect, will be buying more. Yes they are expensive, but they work.