Harken 25mm Wire Forkhead Block with Becket to carry wire halyards and high-strength control lines. 

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 wire halyards, vangs, control lines
• Polished stainless steel strap type fixed shackle
• Sheave Diameter: 1" (25 mm)
• Max. Wire Diameter: 3/32" (2 mm)
• Max. Working Load (MWL): 1000 lb. (454 kg)
• Breaking Load: 2000 lb. (907 kg)
• Weight: 1.02 oz. (29 g)

25mm Wire Forkhead Block with Becket