This device is for holding samples during their preparation prior to imaging in the electron microscope. The design means it can be transferred between the light and electron microscopes as well as trimming devices used to prepare the final sample. It can also be used at both ambient and cryo temperatures down to -110 DEG C. The device consists of a base plate that can be held on the stage of a light microscope. It has an aperture through which transmitted light can pass. In this aperture is a clamp which holds a small transparent plastic sphere the sample sphere. The sample for preparation is bonded to this sphere. The shape of this clamp and sphere means that the sample can be held at any angle to allow for optimal imaging in any light microscope and in the trimming devices, including the ultramicrotome. Once trimmed, the entire universal sample holder can then be transferred into the scanning electron microscope, or held in the ultramicrotome for thin sectioning.