If you are looking for something that can hold your flash unit anywhere you go, Manfrotto 175F-1 spring clamp could be your best option. This clamp is a great product and should be a part of any strobist's basic lighting kit. It provides a great amount of versatility and can be attached to a light stand or clamped into anything. The ball head socket allows you to position your flash in any position you like, allowing you to create your shot however you envision it. It takes only few seconds to clamp it onto to a piece of furniture without fear of marring a surface due to the small rubber feet built into the clamp.
It is very handy for mounting the flash units like SB-600 or SB-800 in places where you can't use the light stand. It clamps very well and it's secure. The plastic cold shoe fits the strobe nice and sung so that you don't have to worry about the strobe falling out. The clamp end is strong and grips things very well. It also has a standard light stand stud on it and a clamp as well to accept a stud from the light stand. It can hold up to 4.41 lbs and rotates 360 degree. The clamp is made up of aluminum and steel and it weighs about 0.73 lbs.
Manfrotto brand is known for the quality products. I own several products from Manfrotto like 055XPROB pro tripod, spring clamp, 498RC2 ball head. They are excellent quality products and I love them. Their build quality is extremely strong and sturdy. Their products are little expensive than what you get in a regular market (non-brand item) but worth every penny and it will pay you off in the future.