Promotional 18cm Optical Crystal Rectangle with Onyx Black Base The optic Rectangles are hand crafted out of perfectly clear optical crystal and Onyx Black crystal and are available in 3 sizes. They have a large engraving area that can be personalised with any crest, logo or wording to create an award that is sure to take pride of place when put on display at home or at work. They are ideal recognition, achievement or incentive gifts and are supplied in a black foam lined presentation box.