Overview Product Description 3" threaded inspection cap without vent line hole, with O' Ring. Product Videos Custom Field Product Reviews Write a Review Write a Review × Dometic/Sealand Dometic/Sealand |Inspection Tank Cap/O'ring w/o vent| 385250020 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name *Email *Review Subject *Comments