I am not a pro-dog walker but I might as well be. I have three cock-a-poos who need plenty of walk time -- sometimes up to four times a day. To reduce the hazard and thus my predictable fallout (literally) from one or more dogs suddenly changing direction, I use this inexpensive device. It's basically the same as the Double Dog Leash, except instead of being one ring you attach two leashes to, it's one unit with three interconnected, 3500-pound nylon leashes. I simply attach all three dog collars (I use the Gentle Leader harness) to each of the brass rings; metal is available, but brass felt sturdier. The physics of three dogs pulling from one vector instead of three has really given me a fighting chance. It tempers the faster dog and encourages the slower dog so I end up with less overall pulling and none of the dogs can dart out in front of my feet as easily.