The #CU30 Bled Double Buckle Curb has a lot of feel on a young horse without the advanced signal of a chain. It is for use on a bridle. I make it out of 1/2 inch latigo leather that has been bled in the center to increase feel. The buckles and wire loop keepers are stainless steel. A very nice transition curb when you need just a bit more signal than a leather strap but don't need the strong signal of a chain curb strap.
Please see Dennis Moreland's Tack Talk article "Curb Your Enthusiasm" to learn more about curb straps: http://www.dmtack.com/articles/tack_talk/curb_straps.pdf