Ronstan RF20101 Single Loop Head Pulley 20mm – Series 20 Ball Bearing BlockThe Ronstan RF20101 Single Loop Head Ball Bearing Pulley (20mm) is a compact, high performance Series 20 block designed for smooth and efficient control line handling on modern sailing boats. Engineered with a 20mm acetal sheave running on precision stainless steel or Torlon ball bearings, this block delivers exceptionally low friction and reliable performance under load, making it ideal for dynamic sailing applications. The loop head attachment

For correct installation:

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🔧 Key Specifications & Benefits

and other simple control systems

Versatile mounting base for RAILBLAZA accessories

✅ Simple plug-and-play installation

this block provides smooth

Ideal for external or remote installations

Marine-grade stainless steel sideplates for durability

this block combines ball bearing efficiency

The Harken 2644 is an excellent choice for upgrading sail handling systems with lightweight

hole centres: 61 × 43 mm