Z Clips are used to hold FG50 alkali resistant fiber glass reinforcing securely at the appropriate height for cast-in-place concrete countertops using Z Counterforms. They should be fastened with a #10 x 5/8" panhead screw (#10 x 3/8" for Euro Form). 100 per box. 1 box will cover approximately 33 sq . ft. Standard- For use with all forms except the thinner EuroForms. EuroForm - For use with thinner EuroForms. Commercial - For Commercial Square Edge Forms, use the standard height Z Clip