Each bin comes with separate lock down clasp for sealing, A Lot to loose pieces to loose down the road for the price.Definitely waterproof and best storage for boat stuffThese bins are HUGE. The price is steep but honestly I don't see these ever breaking. Will I run out to buy a ton of these? Maybe not but if I had the money to splerge again, I would replace my current buckets with these. The plastic is very thick and I could fit in this bin and close it, that's how big it is. It also has these rubber handles on the side that snap the lid into place. These seem like they would be water proof and could fall off of a truck and not break. You never want to buy bins again? These are the bins for you.You know you never know you need waterproof and airtight until there is an incident. I now use these in all sizes. The hooks sometimes fall off before using and easy to attach.Actually have a seal are sturdy and clear to view contentsGreat product. Nice and big, sturdy. And an excellent seller.The best storage box i ever had . Its sturdy and good quality, its worth to buyI have a second home and I ordered these to keep together all the items coming and going. They are perfect. Heavy duty but not too heavy when loaded. The stacking is really handy. Will order some more to organize all my Christmas decorations. Highly recommend