PreHeels+ creates a durable, invisible barrier on your skin that blocks friction from shoes to prevent blisters, irritation and hot spots. The breathable, flexible coating conforms to the unique shape of each foot for optimal coverage, and is hypoallergenic, dermatologist-tested and works with all types of shoes. Barefoot Scientist's one-of-a-kind formulation provides ~4 to 6 hours of protection, which is more than twenty times stronger than most blister sticks. Hypoallergenic. Dermatologist Tested. Vegan. Leaping Bunny Certified. 1.5 fl oz