Jim Dunlop / ECB-124 OFFSET 3 Types Three types of rubber with different heights. From the left in the photo: 9mm x 2 pieces 6mm x 2 pieces 3mm x 2 pieces Diameter: Approximately 9.3mm to 9.7mm (common) Fits the size of Dunlop wah pedals, but also fits Budda and old VOX V847 models. Please secure with instant adhesive, etc. You can adjust the amount of travel when stepping on the switch to turn it on by changing the height of the rubber. You can also change the tread width by changing the height of the rubber on the heel.