The Walk-O-Long was invented by a dad whose daughter started to walk right after he had back surgery. Seems her arms were shorter than the average gibbon (aka human-length), and holding her hands meant bending over in a way that caused excruciating pain.
Me, a year+ of bending over has caused only mild, perpetual pain and a compulsion to do more reverse situps. [note to dads-to-be: do mogul-skiing exercises to help get ready for all the colicky deep knee bends and, later, the stooping.]
Anyway, shorter than any leash (except those used in dog shows, which, it must be said, look eerily similar), the Walk-O-Long is more walking aid than child restraint. It enables parents, &c to stand upright and assist a kid with a little stabilization/lift now and then, as needed. It's padded under-the-arms design was inspired by firemen's evacuation harnesses, and the company's website says it's great for helping special needs or disabled kids increase their mobility.
The only daddy drawback: the fabric options, which range from pink or blue solid to pink or blue Hawaiian print to Leopard or Zebra. Until aftermarket slipcovers become available, I suggest the best color is duct tape.
The Walk-O-Long sells for $24.95 [thewalkolong.com via dt reader ed]