The pic above shows the infamous "Chicken Clip". Basically, it's just a dogbone with two locking carabiners. I constructed this one with a Black Diamond Dogbone (about $5) and two BD Vapor Lock carabiners (about $8/each). Total cost is just over $20. I use the Chicken Clip to pre-clip high first bolts on routes I would like to lead (but don't want to die trying!). To pre-clip - climb a neighboring route, rappel down to the high bolt, clip the "loose" end to the bolt, clip the "tight" end to the rope, lock both carabiners, finish your rappel, then pull the rope. If you pull the correct end, the rope will fall perfectly and will allow you to do a mini-top rope to the first bolt. The Chicken Clip, when paired with an identical clip, makes a quick and easy top rope anchor for sport climbing. If you carry one or two of these around, you'll find plenty of other uses for them as well.