Harken 40 mm Carbo Double Swivel w/ Becket 2639

Harken 40 mm Carbo Double Swivel Block with Becket (2639) – High‑Performance Twin‑Sheave Pulley

Upgrade your rig with the Harken 2639, a premium Carbo Air double swivel block boasting a built‑in becket—designed for high-load control systems on dinghies, skiffs, sportboats, and small keelboats. Crafted for smooth trimming and optimal mechanical advantage, this block excels in main/jib sheets, vang adjustments, outhauls, cunninghams, and other precision control lines.

Material & Design

• Open Carbo Air® construction with carbon-fibre composite side cheeks—30% lighter yet 60% stronger than classic blocks 

• Two 40 mm Delrin® sheaves on stainless steel ball bearings ensure low‑friction, responsive operation under load

Swivel + Becket Features

• 360° stainless-steel swivel shackle allows full rotation, preventing line twist and ensuring consistent alignment

• Integrated becket enables clean multi‑purchase tackles (2:1 and above) without extra hardware

Performance Specs

• Sheave diameter: 40 mm (1⅝″)  

• Max line capacity: 10 mm (3/8″) 

• Working load: 440 kg (970 lb); Breaking strength: 1080 kg (2380 lb) 

• Weight (with shackle): 90 g (3.4 oz); Length: 110 mm (4⅜″)