This scenery in heroic 28mm scale, have been designed by Vae Victis Miniatures and are compaitble with Frostgrave, Dungeon saga, pathfinder,  and DND, Last war. Turnip28, Forbidden Psalm and other Old hammer games.
 
This set contains 4 pieces 
1x Sewer entrance open
1x Sewer entrances with rope
1x ladder piece 
1x Iron grate
 
The middle piece on the first Picture is an example of the open sewer with Iron grate added.
 
They come in ABS like resin.
 
Please note 3D printer resin is not like the Resin used to make injection moulded miniatures it can be a little more brittle.