Glacier Tanks non-pressure manhole access ports come with silicone seals and open outwards. All manholes are made from stainless steel SS304 and most come standard with a 4 inch neck, but longer neck sizes are available via special order. Each tank manhole is secured by an even 4, 6, or 8 count of knobs (please check product description). Manholes are ideal for smaller tanks sizes.
Duane Teach
Michael C