The RUCO V 440 bookends (in Set of 4) serve their purpose. They ensure that the books do not fall on the shelf. They are 14 cm high and 8.5 cm wide, from antrazitfarbenem plastic. The plastic is naturally not as stable as metal. Due to the dimensions you should use these bookends for normal high books. With an open shelf of one meter length, it is better if you used two pairs of bookends. The price is very cheap. From me there as a result of 4 stars.