Open top, 30x40 cm/12x16 inch, 50 Pcs Packing. | These anti static bags are specially for ATX mother board, Graphics Card, GPU, electronic device. | These ESD shielding bags are made of PET 3 layer composite material, brand new CPP and electronic plating aluminum, no toxic material, can prevent static electricity very effective. | Surface Resistance(inner & outer) is 10^8-10^10(Ω), thickness is 0.15mm(double sides). | Thank you for choosing & trusting us and we would be really appreciated if you could share any reviews about our product being used. :)