Prothane 7-504 GM ENGINE MNT TYPE A SHORT PR. PROTHANE has exclusive and innovative technologies that guarantee stability and high performance every time. Each of our products is specifically tailored to exact specifications of resiliency, performance and durability for the specific application. That is why the PROTHANE products are greatly superior.Urethane/Polyurethane is a term used to describe a family of elastomers (any compound exhibiting the characteristics of natural rubber; stretchy and elastic). Poly meaning "many" and "urethane" denotes the classification of the chemical structure. Polyurethane or Urethane for short is used as a solid cast material bushings, mounts, mount inserts, etc. That can be compounded as soft as a rubber band or as hard as a bowling ball. Each of our products is specially formed to exact specifications for resilience, performance, and durability for the specific application. Prothane GM Motor Mounts - Type A Short - Red. Processing begins as soon as an order has been placed, therefore we cannot change, cancel or modify orders once they have been confirmed. Most e-mails are answered within 24 hours, including weekends and holidays.