Extreme vibration attenuation (eva) is the latest generation in vibration dampening technology. The enhanced performance comes from the special composite foam center which is structurally more sound than cork. EVA is not affected by oils or chemicals that can break down cork and is much more effective at vibration dampening than solid rubber. Designed to withstand 50 psi. 4 in. X 4 in. X 7/8 in.