This is knit in a very easy 2 round repeating lace pattern (1 round of simple lace, 1 resting round of just knit) and can be adjusted longer or shorter depending on the amount of yarn you have available.

Knit it as written to have a long, large loop large enough to pull over your head as a smoke ring, or decrease the number of repeats to make a skinnier tube.

Size 4 needles make a nice, open, lacy fabric.