A seal device for sealing slide-out room opening in recreational vehicles. The seal including a base; a bulb; an alignment aid member; and a positional member. The base having a proximal end, a distal end, an inside portion, an outside portion, and a perpendicular member. The bulb having an arcuate portion, a sidewall portion and a curled end portion. The positional member extending perpendicularly to the base distal end in opposite direction of the alignment aid member. The seal device may further include a flap extending co-linearly from the base distal end and a fastening system.