Harken 51mm Thru-Deck High-Strength Block allows lines through the deck and bulkhead.

Harken's Lightweight, low-friction blocks with high-load composite bearings carry wire halyards and control line cascades. Side-load balls reduce friction from twists or unfair leads on 304-311. 300-303 has thrust washers. Blocks open to allow passage of swaged wire. Hard Lube-anodized sheave for strength and corrosion resistance. Cheek blocks include fasteners.

• Impregnated Hardkote anodized aluminum bearings
• Side-load carbon-black Delrin® washers
• Use for control lines
• Sheave Diameter: 2" (51 mm)
• Max. Wire Diameter: 3/16" (5 mm)
• Max. Working Load (MWL): 2000 lb. (907 kg)
• Breaking Load: 4000 lb. (1814 kg)
• Weight: 5.75 oz. (163 g)