Possessing the same fluorescent qualities as the Matilda Imperial Fibre Optic Rulers own rulers, the fibre optic squares come in a large selection of sizes designed to suit any quilting application. An absolute must for accurate quilting blocks. Cut to an accuracy of 1200 dpi and the only ruler that is Laser engraved to the same accuracy. Engraved with the marked lines as closet of the fabrics as possible. This unique green colour works on any colour fabric especially in low light. Simply Brilliant!