Raisin Solid Interlock Knit by Birch Organic is the newest batch of solid interlock knits, featuring 8 new colors and 4 of our all time best sellers. Our interlock knit solids are 58 wide, 95% cotton, 5% elastane, and 220 gsm. Interlock knit is a stable knit perfect for garments and decor that require a bit more structure.