I'm not a BST mod but I believe it was closed because you have items listed that belong in there appropriate BST forums. Tanks must go in the Air system forum, Hoppers in the Hopper forum and so on.
BST rule 12
• Grouping items will no longer be acceptable. If you have a pile of items to sell separately, make separate posts in each respective forum. You can sell a marker as a package with other parts for one price, but please post it in the appropriate marker forum. (ex. You can't have 3 air systems, 8 barrels, 3 guns and few miscellaneous parts all in one thread in one forum.)