A decent saxophone ligature can make a sizeable difference to your sound and responsiveness from your reed and mouthpiece. Material ligatures such as Rovners and Silverstein's work very well with metal mouthpieces. Metal ligatures can be more fiddly to use, but they release the upper frequencies and let the reed resonate very freely, which works especially well with stuffier, darker mouthpieces.
Not sure what ligature you need? Our team of saxophone specialists is on hand and always happy to help if you have any questions!