This pattern also contains instructions for a Sport-weight version and a heavy-weight version.

Sport-weight suggests #4 (3.5mm) and #6 (4mm) needles and a gauge of 24 stitches to 4 inches in Stockinette on larger needle.

Heavy weight version suggests one skein Classic Elite La Gran Mohair, #7 (4.5mm) and #9 (5.5mm) needles and a gauge of 16 stitches to 4 inches in Stockinette on larger needles.

From the book, ” The classic beret never goes out of style, and the directions allow you to knit it in three weights of yarn. The heavy-weight gauge is quite nice in mohair, but experiment and find the yarn that is just right for the look you want.”

See also NL14 Three Gauge Beret