Powerflex Lower Engine Mount Insert PFF16-720PFF16 720 Lower Engine Mount Insert is made in our Yellow 70A durometer material for increased mount longevity and performance. Designed to fill the voiding in the OE rubber mount, it smooths out gear changes by stiffening and supporting the often perished rubber bush, which is common for failure on tuned vehicles. This will provide a more precise and settled transmission response during acceleration and deceleration. A small increase in NVH, usually