The Farnsworth D15 Dichotomous Colour Test is used for detecting congenital and acquired colour defects. The test contains a reference disc holding notation 10B54 and 15 numbered discs which make up an incomplete colour circle. The patient arranges the discs and the evaluation of the patient's arrangement separates "normal" colour perception from moderate and strong defects in deutan, protan or tritan axis colour discrimination. This is the standard version of the test; we offer a magnetic version where the discs are contained in a sealed plastic box and arrangement is achieved using a magnet. This has our catalogue number SGR-224-FM.