Line sizes range from 20/400 to 20/10 equivalent with continuous text line sizes ranging from 20/100 to 20/20 equivalent. Notations are indicated in Snellen in Feet/ Meters, LogMAR, Decimal, Letter Size, and Diopters of Add. These cards come with a 16" (40 cm) measuring cord for easy use. Dimensions: 10" x 8" (25.4 cm x 20.32 cm). Testing distance: 16"/40 cm. Printed on styrene for long-lasting durability.