This is the Saxnolite neck screw for saxophone by GAT Custom Brass. Type A M4 0.75L, so it's for Supreme and Signature models, and I used it with a Supreme. I'm a little hazy on the material, but the image says "bronze," so I'm pretty sure it's bronze. My impression when playing was that it made the tone brighter! I didn't use it very often. #saxophone #Saxnolite #saxophone