Small and light aluminum alloy materialHigh hardness, metallic luster, not easy to rust, lightweight and durable aluminum alloy material is more conducive to heat dissipationThe Aluminum Case the metal shell is more conducive to heat dissipation, and comprehensively protects your motherboard.Full package and full protection After repeated testing, each hole is highly matched to the motherboard, and the protection is more thoughtfulSpecially made for raspberry pie 4b, raspberry pie 4b is different from 3b+/3b interface, and the shells are not common to each otherApplicable : For 4BColour:blackMaterial:Aluminum alloyPackage Contents:1 x Aluminum Alloy Upper Cover1 x Aluminum Alloy Lower Cover3 x Thermal Pad1 x Wrench1 x Cooling Fan8 x ScrewOnly the above package content, other products are not included.Note:Light and different displays may the color of the item in the a little different from the real thing.The measurement allowed error is +/- 1-3cm.