The blue area in the heel cups are for extra soft for providing greater cushioning of sensitive areas such as bony part of the foot which helps in giving comfort in standing and walking.Extra comfort: medical grade silicone soft gel cradles the heel for extra cushioning, stability and comfort100% brand new and high qualityThese heel cups are really helpful for heel ankle pain, plantar fasciitis, heel spur, knee, back pain etc. The heel cups are hypoallergenic, non-toxic, non-flammable and odor free.Protection: keeps skin comfortably moisturized to prevent dry skin and protect skin from cracking