Knitting Pattern: Felted Nalgene Cozy

When felting a Nalgene holder with a Nalgene bottle in it, the washing machine makes some funny thumpy sounds. I'm curious what it'll do during the spin cycle.

Felted Nalgene Bottle Cozy (which needs to be tweaked).

Great for keeping your Nalgene from "sweating" water all over your stuff when you shove it into your bag, fresh from the fridge, in the morning.

CO 40 sts worsted weight yarn on a size 11 circular. Join.
Knit around for 11" (but I think it should be closer to 10"- this guy seems a little long)
Decrease every other round, starting with K6 k2tog, until 20 sts remain, then decrease every round until 5 sts remain. Pull through and secure.
Pick up 6 sts at the top. St st for two rounds, then garter for 10.
Decrease to 5 sts and work strap: K3, yf, sl 2 pwise.
Continue in pattern til the strap is almost as long as you want it.
Go back to garter, increasing one stitch, garter 10 rounds, st st for two rounds (i.e., make a mirror image of what you did on the other side). BO. Sew to opposite side of holder.
Felt til it's done.