I purchased a set of these and use them on my sop and bari sax mouthpieces. Besides being gorgeous, they are screw-less so way easy to adjust.
The Borgani Flexitone ligature is a remake of the classic Selmer Magnitone adjustable ligature. Available in nickel silver or bronze, the ligature is flexible but strong, and adjusts throughout a large range of sizes to fit snugly on your mouthpiece, firmly holding the reed on the table while being flexible enough to allow the reed to vibrate. There are two sizes, small and large. Small fits clarinet, hard rubber soprano, and metal alto and tenor pieces. Large fits hard rubber alto and tenor pieces.
I purchased them from my friend Matt the owner of Stohrer Music.