The 4-position Axio Examiner objective turret is more complicated to use than the nosepieces of most other microscopes. There is no electronic control through the software or through a touchpad, so it must be manually rotated. However, it doesn't simply freely rotate. Instead there is a dial on the front on the turret that must be rotated to the 'up' position to allow the user to rotate the objectives using the metallic ring above the dial (see gloved fingers in the image below). The dial must be rotated to the 'down' position to lower the selected objective lens for imaging.