Universal Hubs - Molded high-strength glass-reinforced composite with integral steel reinforcing plate. 6-1/2” O.D. Color: Black. Fits 1” dia. prop shaft. Accommodates most mounting plate bolt hole patterns from 2-1/4” to 3-1/4” dia. and ¼”, 5/16” or 8mm prop mounting bolts. Assembled hub is 2-1/4” thick. (Two identical halves per assembly).