I must preface my answer by saying that mouthpiece selection should be based on feel, confort and sound and not soley on specifications. To be able to fully understand what each specification means, I recommend checking out the Brass Mouthpiece Buying Guide that can be found here: http://community.music123.com/docs/DOC-1679
The most common specifications are for diameter and cup depth. If these can't be found in the item description, the manufacturer's website is the next best place to look. Most manufacturers list cup diameter, cup depth, rim contour, backbore and throat specification. If you need help comparing specifications from several manufacturers, feel free to give us a call at 888.566.6123 or post another question here.
