30" Air Compressor 6 Groove Belt One brand new 30" air compressor flat poly v-belt made in the USA. This is a flat 6 rib belt most commonly used on air compressors, but will work for many other applications. This belt measures 9/16" wide and is 30" long. Note: If you have an old compressor belt that you are trying to match up to this one, it could be stretched and be a little longer than it was originally. Please check to see how much motor adjustment you have to know if the 30" new belt will work.