High breaking strength clamp used to construct scaffolding.
A scaffold is a temporary structure used to support crew and materials during the construction or maintenance of structures at height. Made of wood, bamboo, or metal, there are many types of scaffolding. A certain type of scaffolding uses steel tubes and clamps using diagonal tubes to stabilize the scaffolding. Horizontal tubes, and thus walking decks, and vertical tubes, or legs, can be placed at any distance as permitted by engineering constraints.
Found in construction sites.