The soft custom durometer used in the “EuroDamper” rings physically dampens vibrations caused by speaker vibration in combo amps. This greatly reduces or in most cases eliminates tube rattle. These are also great for reducing mechanical noise in Hifi amps. The large “EuroDamper” rings measure 1.100” (27.94mm) inside diameter for a snug fit on EL34, KT77, 6L6, 6L6GC, 5881 power tubes and 5AR4, GZ34, 5U4 and 5Y3 rectifier tubes. The OD measures 1.80” (45.72mm) and the thickness measures .375” (9.25mm). These are also available in a smaller size for preamp tubes such as 12AX7, 12AU7, 12AT7, etc and EL84 and EL844 power tubes.