The pattern is for an adult open work crochet top written in 5 sizes:

Small - finished chest circumference of 35 inches
Medium - 39.5 inches
Large - 44 inches
XL - 49 inches and
XXL - 54 inches

Sport weight/2/fine yarn (19 wpi) and size D/3.25 mm crochet hook. The instruction includes plenty of photos.