Abstract: An optical element providing greater conversion efficiency and comprising a pyramid having a square base and four triangular faces of equal size and shape meeting at the apex. The optical element can also comprise an octahedron or double pyramid of similar configuration.

Abstract: An improvement for a cable terminal which includes a terminal carrier 1 and a terminal clamp 12 tracked in the carrier where a flexible locking tooth 8 on the terminal carrier 1 works in conjunction with a toothed rack 24 on the terminal clamp 12. In this improvement the terminal carrier 1 is in the form of a hollow cylinder or cuboid whose upper edge includes two opposed grooves 2, 3 to accommodate a cable, and the terminal clamp 12 includes a clamping rib 19, 20, 19a, 20a which acts on the cable from above and/or laterally, centrally to the grooves, and which can be axially displaced and locked.