Parachute stopping is designed the like a round or oval parachute and is used to seal entry in an area with differential air pressure of at least 0.30 in. wg. The stopping perimeter should be at least 1.5 times larger the the perimeter of the air way when used.
Inflatable stopping is for fast, temporary air stopping in a mine or tunnel with inflated perimeter to allow for an access door. Built to your specifications.