In Europe the use of large precast elements for apartment block construction, if not exactly common, no longer rouses any very great interest. A number of concrete products manufacturers now specialize in the supply of building units (floor slabs, wall elements, steps, beams, trusses) in sizes which are the maximum practicable within transportation and erection limits. A Dutch contractor has now gone one step further and taken his precasting yard to the site, reasoning that site precasting combines the advantages of both precast construction and flexible site operation. Normal job savings are said to be a good 5 percent over conventional plant precast construction, although it is acknowledged that the design of the building has considerable influence on this figure. One important consideration in this development is that plant precasting must inevitably involve a large degree of standardization, whereas the concrete contractor is traditionally free to adapt himself to the client's wishes. In other words an architect or designer using plant precast construction is always bound, to a greater or lesser degree, by the products that he has chosen to use. The site precaster says to the client, in effect: "You go ahead and design the building, we'll find some way of precasting it." This means that the designer has full freedom in choice of room sizes and layouts, and, what is often a very important factor, in choice of cladding medium. In multiple-family housing the question of visual appearance often exerts the greatest influence on whether a design is accepted or not.