Fox Blocks FOX-HV CLIPS HV Clips - 250 per Box - These HV Clips are for use with ICF Installations. Fox Blocks ties are designed to be perfectly balanced, spaced at 8″ o/c horizontally and vertically, giving flat walls post concrete. The HV Clip has been designed with eight bends, allowing one clip to work horizontally and vertically. Using the Fox Blocks HV Clip eliminates the need for truss wire completely on jobs.