No particular yarn is suggested for this but Wendy’s 5 ply Guernsey works nicely for this Aran Cardigan with set in sleeves. The pattern does not use charts or stitch diagrams.

Gauge on #3 US needles in K1, P1 raised rib, (not expanded) 7 1/2-8 3/4 stitches to 1”. 7 3/4 - 8 rows = 1”.
On #5 needles in Aran Patterns 6 3/4 stitches to 1” and 8-9 rows = 1”.

A Test Gauge Pattern is supplied for swatching

From website:

Level: advanced

Knit on #5 needles, this is a hard-to-find Aran cardigan as it is knit with sport weight yarns, a lighter weight than that used for most Arans. Galway is the result of customer requests from the early years in my yarn shop! The smaller needles paired with the Aran patterns and the buttonhole work in the Banjo Cable front bands demand attention to detail and the expertise of an advanced knitter.

Aran patterns show to best advantage, with great stitch definition and clarity, knit in smooth worsted-spun yarns.

Sizes 34 through 44.