In one embodiment, a manually operated internal Venetian blind for raising/lowering a plurality of slats is disclosed, and comprises a stationary bearing housing, a longitudinally displaceable bifurcated bearing block, a counterweight interconnected to the bearing block and housing at least one internal magnet, and a first linearly displaceable actuator disposed outwardly to one of two glass sheets and provided with at least one external magnet at a fixed distance from the internal magnet. The displacement of the first actuator is significantly less than the displacement of the longitudinally lowest slat due to the winding of central cords around a ball bearing housed within the bearing block. In another embodiment, a device for tilting the slats to which two outer cords are affixed is provided with two laterally oriented sides and an annular protrusion rotatably supported by a suitable assembly secured to a support surface and transversally extending outwardly from each laterally oriented side, such that the tilting device is rotatable about a transversal axis coincident with the axis of the annular protrusions. An external blind is also disclosed.