Gauge = 13 sts/3”, or 4.3333 sts per inch.
Pattern gauge = 4 sts per inch, so these slippers are smaller than the design intended (too tight for my size 9.5 feet). They will be donated.

In instep section in the pattern, decrease missing:
Next (RS) row: K1, ssk, work to last 3 sts, K2tog, K1

Worked 3.5” before instep., 7.5” from CO before heel.
Used 5.5 mm to work 3-ndl BO.
With 4.5 mm (b/c worsted weight ribbing), picked up 17 sts each side + the 4 on the holder.
Decreased down to 36 1st rnd of ribbing.
12 rnds (incl. PU) before BO with 4.5 mm.