Fig. shows an image of the polariser mount, which allows for two alternative mounting methods depending on the thickness and fragility of the part. The mount is formed from two interlocking 3D-printed plates: a mounting plate and a clamping plate. The thin-film polariser is placed into a central hole in the mounting plate, where it rests against a lip. The optic may then be secured by means of a rubber-tipped M3 set screw or, if it is thin or fragile, it may instead be secured using the secondary clamping plate and a soft 3D-printed o-ring formed from thermoplastic polyurethane (TPU). The o-ring is placed over the optic, followed by the clamping plate. The two plates are then lightly pressed together so that the optic rests between the lip in the mounting plate and the (slightly-compressed) o-ring, ensuring even pressure around the circumference of the optic. (Note, if you choose to use the first attachment method and do not have access to rubber-tipped screws, then we have found that inserting a 1-3 mm length of soft tubing between the optic and the screw-tip is an effective alternative, see Fig. . We use 2-mm OD polytetrafluoroethylene tubing for this purpose, but any soft rubber or plastic should work). A set-screw on the underside of each plate engages with the lowest rail of the cage, allowing the position to be locked.