The 20" x 30" bag is perfect for your laptop(all sizes), gaming systems, radios and extra accessories. This Faraday bag features an outstanding 38 lbs. puncture resistance. The multiple layer construction provides full protection against ESD, EMI/RFI and tribocharging. Electrical Properties: EMI Shielding (MIL-B-81705-Rev-C): >40 db Between 1 & 10 GHz. It has always been the suggestion of Tech Protect to nest or place one bag inside of the other to give optimal protection against EMPs and Super EMPs. Resistivity-Conductive Metal Layer (ASTM D-257): <2 Ohms/sq. in. avg. Surface Resistivity (both surfaces) (ASTM I-257 @ 12% RH): <10 12 Ohms. sq. in. Static Decay (FTMS 101C, Method 4046.1 5000 to 0 Volts): <0.05 Seconds Capacitive Probe Test (High Voltage Discharge) - (EIA-std 541/Appendix E-1 KV): <8 Volts Charge Generation-nominal (Modified incline plane Avg. nC/sq.in.):Teflon: -0.09 Quartz: +0.10 Physical Properties. Total Thickness: 7.0 mils. Light Transmission (ASTM D-1003-77) <.01%. Tensile Strength (ASTM D882-83 Method A) 735 lbs. Tear Strength: (D1004-66 - Notched) MD: 5.8 lbs.TD: 7.5 lbs. Burst Strength (FTMS 101-C Method 2007 1a) >130 psi. Puncture Strength (FTMS 101-C Method A): >38 lbs. Elongation (ASTM D822-83 Method A) MD: 40%TD: 74%. Heat Seal Strength (ASTM D-1876-72 Vertrod Sealer): >11 lbs./in width MVTR (ASTM F-1249 @ 100°F 100sq. in./24 hrs) <.0006 gms OTR (@ 100% Oxygen 100 sq. in./24 hrs) ASTM. Because our Faraday Bag utilizes the most current metalizing technology, its moisture barrier performance exceeds foil laminates for low Moisture Vapor Transmission Rate (MVTR), particularly after flexing. In other words whatever you place in the bag and seal properly is going to stay dry also!