Illume Aran

This base is a dense aran/heavy worsted 100% superwash superfine merino wool yarn with 3 plies and 180yds/160g! Yes, 160grams. It's a very heavy yarn but its gauge is that of an aran weight or heavy worsted weight. With a 4.5mm needle, knitting 18 sts and 28 rows will give you a 4x4inch swatch. 

I love this base because of how thick it is and the fact that it makes for a really heavy and luxurious FO with the softness of the superfine merino property.