My chain is hooked to the right hand side D ring, then it goes around behind me and is hooked to the left D ring, then it continues for 20 ft. or so (however long you want it) Thats the part that goes around the tree. There are two snaps hooked up to the right side D along with that end of the chain. There are two so that you can take up slack with one or the other and you always have one still hooked up. You can use that same method to pass over limbs also. These snaps are just hardware store items and do not have screw locks on them, but you are using two so the chances are pretty slim that they would both come un hooked at the same time. The chain makes a full circle behind me so that i can un hook the chain from the D rings on both sides and render myself around the tree without moving the chain. this is some times needed (not very often) because it is possible for a chain flipline to half hitch around a stub on the back side of the tree. that is a real problem mostly in old growth redwoods(or any other big tree), that is why you need to be able to render yourself on the chain. When you flip a chain that flip will carry a lot further around a big tree. I think rope is the way to go for small trees, but chain for the biggun's. Of course you would not want to use chain around power lines. Some people put down chain because they say it is only as strong as its weakest link. that is true, so make sure you get a chain you know you can trust! I am not saying chain is the right way to climb or the safest way, but it works for me! Gotta go got 2 tree jobs waitin on me!