For 4B 3B 3B+ Aluminum alloy cooling bracket housingThis is an aluminum alloy heat conduction heat sink, can be installed heat dissipation fan, specially used for 3B/3B+/4B motherboard chip heat dissipationIt is molded with imported high-quality aluminum, heat conduction and heat dissipation, which can control the heat generated by the chip when the motherboard is working and running, and keep the motherboard operating temperature below the normal value and stable operation, so as to extend the service life of the motherboard.Beautiful appearance, easy to use and install. and high qualityName:Metal CaseAccessory Type: CasesCompatible With: for 4B/3B+/3BType:protective caseType:Heat Sink Shellcolor:Black + silverMaterial:Acrylic + aluminum alloyPackage Contents:1 x Acrylic lower cover1 x Aluminum alloy cover (silver)1 x cooling pad1 x Screw accessoriesOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.