Hey, little late of a reply but that particular length is quite difficult to find. You'd likely be better off buying a roll of them and cutting them to size. You can find these pretty easily on Amazon, look for the ones with pads to solder onto at each cutting point.
If you are not comfortable with soldering, you can get connectors that will clamp onto the pads, however my experience with them is that that method creates a poor connection, and the lights are unreliable.
