EPDM foam is a kind of rubber foam, soft foam material, EPDM Chinese name is EPDM rubber. EPDM is divided into closed-cell foaming and open-cell foaming. The closed-cell foaming material has an independent pore structure, and the closed-cell foaming material is separated by a wall between the pores and is not connected with each other. They are mainly small bubbles or tiny pores. The open-cell foaming material is mutually connected with the bubble and the outer skin. They are not independent bubbles, mainly large bubbles or rough pores. EPDM characteristics, thermal insulation characteristics: because foamed materials contain a lot of air or other gases, not suitable for recycling, especially closed-cell foamed materials, they have completely separated independent bubbles. The material can slow down heat conduction obviously, has very low thermal conductivity, and combines the softness of the material itself with good resilience. Low water absorption: for closed-cell foamed materials, separated bubbles, combined with selected rubber or plastic materials of hydrophobic performance, can prevent water vapor penetration, become an ideal sealing material. Cushioning high elasticity: rubber itself is known for its high elasticity, in the rubber is processed into foamed materials, still maintain a high resilience, this is very suitable for the field of cushioning high bullet shock.