Block of three, four and five pigeonhole letterboxes. In combination they provide the total number of pigeonholes starting from 3 units. High, narrow and deep their relation to the wall is like a book on a shelf. The lock can be opened and closed without using a key, if it is so desired. The unit is formed simply by placing the various blocks against the wall. These mailboxes have been approved by the Spanish Post and Telecomunications Authority. Body of steel plate of 0’7mm, painted with with acrylic lacquer in black RAL 9005. Front door in polished stainless steel plate of 0’7mm, with transparent perspex window. Labels in white fine cardbox. Lock with recoil spring. 2 keys for each element included. One of the special characteristics which makes this mailbox different from other on the market is the locking. This lock can be opened and closed without using a key, if it required. Lluís Clotet and Oscar Tusquets designed their famous A Sardinel mailboxes in 1975, when they still worked together as Studi Per. That mailbox design was tall, narrow and deep. It was to be fitted a sardinel, that is to say, edgewise like bricks in a building or like an encyclopedia on a shelf, forming an orderly block. In this way it offered a larger capacity than traditional mailboxes, while visually occupying much less space. Its chief novelty lay in the fact that it was filled from the top, something that became important when people began to receive the first subscriptions to newspapers and magazines at home. Over the years the design evolved and was improved until the current 3-4-5 was reached.