Luxe's thermo performance riser (also known as "TPR" formula risers) are the best on the market. They act as a hard riser, but offer the vibration dampening of a shock pad and also allow enough flex to adhere to all types of concave. They feature new school and old school truck holes. They come in 1/4" and 1/8".
Luxe is the company that brought to you Remember Hoots!