Regenstein Library, University of Chicago Chicago architecture, The Laylo Sleeper Sack Duo (sheet + Comforter). For babies 6 24 months old. Sheet + comforter combined into one wearable set. Two layer design lets baby cool down or warm up. Hidden snaps attach the comforter to the sheet sack. Inverted zipper allows easy diaper changes. Quilted comforter has double sided zippers for side unzipping. Allows sliding on or off without waking the baby. Wearable sheet sack: 100% jersey cotton; 5. 3 oz (150 gsm); 0. 5 tog. Quilted comforter: 100% jersey cotton front and back; polyester fill. Sheet sack dimensions: 34"L x 20"W. Quilted comforter dimensions: 30"L x 20. 5"W. Patented two layer sleep sack bag feature.