2×1 Ribbed Knit Fabric from Mind the Maker:

This lovely indigo night organic cotton rib is perfect for cuffs hems and necklines. Colors match perfect with our brushed sweat fabric. Or use it to make a nice basic top like the skyline tee or even a bralette. It has a nice structure while still having a good amount of stretch. The indigo night color is a nice deep dark blue.

Details:

Width: 43″
Composition: 95% Organic Cotton / 5% Elastane
Weight: 9.8 oz/sq yd
Fabric Type: Knit
Color: Indigo Night
Care Instructions: Cold wash, delicate cycle. Do not tumble dry.