Limestone Thermal Bottle Sleeve Lt Green by thinkbaby 1 Cover Limestone Thermal Bottle Sleeve Lt Green 1 Cover In creating a sleeve for Thinkbaby bottles we looked carefully at the solutions on the market. We wanted a material that would provide maximum insulation and protection. But. we also wanted to see how eco-friendly that we could make the sleeve. Our investigation took us to our friends at Patagonia. Patagonia largely pioneered the use of Limestone based neoprene to replace traditional neoprene for their wetsuits. Thinkbaby's sleeves are made from Limestone. They feel just like traditional neoprene. We have made them in 4 colors. They will not only protect the bottles but will provide significant insulation. Please note that we made them fit tight so they cannot be easily removed by a toddler. Warnings Keep out of reach of children. As with all dietary supplements consult your healthcare professional before use. See product label for more information.