This is a beautiful aluminum straight mute for bass trombones made by Tom Crown in the USA. The mirror finish is stunning, and the lively tone of these mutes is captivating.
The version with a copper bottom has a modern metal mute sound, with lots of sizzle. The copper is softer metal and may be slightly more prone to denting if not treated kindly. The all aluminum version is lively, but with less bite than the copper. It's also slightly lighter.
The corks are thicker than some other brands, which allows you a more open feel as is, gives you some room to file them and make a custom fit for your trombone.
For most players, the thick corks may need to be cut or filed, great sound, drill a small (1/8") hole in the edge if playing low Eb with the mute gives you a woof tone. 222g
Pictured is aluminum with copper bottom.