Fox Blocks FOX-S800 8" Straight Block - 12 per Bundle - These Straight Blocks are used for ICF wall installations. The Straight Block typically makes up between 80-85% of the ICF wall assembly on most residential and commercial jobs. This block has six strong, full-length injection, molded plastic ties made from Polypropylene (PP) regrind resin that are well marked with the words “Fox Blocks” located on both sides of the block.