Fox Blocks FOX-C645 6" 45 Degree Angle Block - 9 per Bundle - These blocks are used for ICF wall installations. The 45 Degree Angle Block typically makes up less than 5% of the ICF wall assembly on most residential and commercial jobs. This block has five 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.