Spenco® Slip-In Insoles are make exclusively with closed-cell nitrogen-injected Spenco material. This unique cushioning system provides a soft comfort fit environment to help absorb shock, reduce friction and improve overall foot comfort. Spenco® Slip-In Insoles awarded the Seal of Acceptance by the American Podiatric Medical Association. Years of proven use and high quality, these slip-in insoles provide long lasting heel to toe comfort. They are washable. To fit your fire boots, trim with scissors.