75% Superwash Merino Wool, 25% Nylon

From Knitpicks:

Felici is a play on the Italian word for “happy” and “glad” - your feet will be dancing with joy! The superwash Merino is 19.5 microns (layman’s translation: super-duper soft). The nylon lends strength and durability to the wool, making it suitable for the constant wear socks get. And the machine washability means you will be wearing them constantly. The fun four-color sequenced stripes also have varying widths so a full repeat takes about four inches of stockinette in an average adult sock size. You could also try textured or lace patterns to add another dimension to the waves of color. From subtly tonal stripes to neon brights, this yarn will keep you eagerly anticipating the next color change. Have fun playing with the stripes in other small projects like hats, mittens and baby clothes.

Note: Each Felici colorway is a limited edition. Colors will be retired after they sell out. The newer colorways have six stripes (two sections of three stripes each). Each stripe is about 1/2” wide, for a total repeat of about 3” in an average adult size sock. The older colorways that are now on clearance have five alternating stripes each about 1/2” wide, for a total repeat of 2.5” in an average adult size sock.

Note: For the first incarnation of Felici only: If you want the stripes to match across a pair of socks, make sure to check the stripe sequence when you start. Each color appears twice in the sequence, and each appearance is a different width. It is really a lot of fun to let the stripes work up randomly for each sock.