Type 109 hook strip type threshold can be provided in either ALUMOGRIT® (cast aluminum) or FERROGRIT® (cast iron) Type 109 comes in standard height of 1/2″, standard widths are 4″, 5″ and 6″, standard surface is fluted abrasive surface. Other heights, widths, and intermediate dimensions to order. Lengths are made to order. Maximum length is 8’6″ in ALUMOGRIT® and 6’0″ in FERROGRIT® (lengths over maximum will be made in equal sections).