Abstract: An attachment device is described for attaching a part to a structure. The part may be, for example, an optical element such as a lens or a mirror, that is to be attached, for example, to an optical instrument such as a scanner used to scan biological materials. The device includes a base and two or more holding elements coupled to the base. The holding elements may include a first group of two or more opposing holding elements of a first length and a second group of two or more opposing holding elements of a second length shorter than the first length. Each holding element flexibly engages at least one surface of the part when the device is engaged with the part. A third group of two or more opposing holding elements may also be provided that also are shorter than the first length and that rigidly engage the part. The base and the holding elements may be formed of a single piece of flexible material.