There are three foil products listed here. RF Shielding Foil provides shielding against radio frequency, while G-Iron products provides shielding against magnetic fields. G-Iron ArmoFlex can also provide electric field shielding if it is grounded.
For Radio Frequency EMF Shielding
RF Shielding Foil. Provides shielding against radio frequency EMF. Also provides AC Electric Fields shielding when grounded. Roll onto desired surface and staple to secure. Can be applied under drywall, under shingles on roof tops, in the attic, under stucco and plaster. Overlap sections by 4-6 inches and tape the joints with “aluminum foil tape”. Sold in 125 foot rolls, 4 ft wide.
Use coupon code “YSL” for a 5% discount for this or any other products by Safe Living Technologies.
For Magnetic Field Shielding
G-Iron Flex. Provides shielding against magnetic fields. Flexible and easy to cut to size (caution: sharp edges!). 25.3 inches wide. Sole by linear foot/meter, or a roll of 40 feet. 
G-Iron ArmoFlex. Provides shielding against magnetic fields. Also provides electric fields shielding when grounded. Flexible and easy to cut to size (caution: sharp edges!). 25.3 inches wide. Sole by linear foot/meter, or a roll of 35 feet.