Diabetic medical insole consists of three layers. Memory foam layer is used in this insole, which takes the shape of people's feet and prevents tension and pressure in the feet. This insole prevents diabetic foot ulcers caused by improper pressure distribution.
The sole is the bottom part of the shoe. It is sometimes referred to as two separate pieces: insole and outsole. The insole is the part of the shoe that has direct contact with the bottom of your foot. The shoe's outsole is the portion that contacts the ground when you walk.
Without going in pros and cons of different materials it can be said that PU (polyurethane) is the best .It is reasonably light, good cushion, durable and LEAST SLIPPERY on wet surfaces but little expensive and very few flip flops have PU soles.(Inblue)
PVC is cheap, durable but heavy and little slippery.
Toe Cap, Toe Vamp, Tongue, and Outer sole are the most basic components of a shoe. However, other minor components make up the remainder of the shoe. Collar, Heel Tab, Heel Counter, Logo, Midsole, Foxing, Eyelets, Insole, and shoelace are among them.