Description
Series 25 Ball Bearing Orbit Block™ – Lashing
Single sheave ball bearing block with becket and lashing head.
The Series 25 Ball Bearing Orbit Blocks™ deliver superior strength, reduced weight, and exceptional performance for high-demand dinghy and small boat applications.
Designed with competitive sailors and performance boats in mind, these compact 25mm blocks are engineered to achieve the highest possible strength-to-weight ratio. Featuring Ronstan’s renowned high-compression strength acetal bearing system, the Series 25 BB Orbit Blocks are a lightweight yet durable solution, ideal for control line systems such as mainsheet and spinnaker sheet turning blocks, cunninghams, and cascading vangs on dinghies up to 4 metres.
Each block has a stainless steel hub for versatile lashing attachments and through-sheave becket functionality, making them adaptable to a wide range of rigging setups. The hub accommodates up to 4mm (5/32″) lashing and ensures maximum efficiency without compromising reliability.
Features:
- 2-stage ball bearing system.
- Suits up to 8mm (5/16”) lines.
- Hollow hub for becket take-off.
- Lashing blocks suit up to 4mm (5/32”) lashing.
Specifications:
- Max. Rope diameter (in): 5/16
- Sheave diameter (in): 1
- B.L. (lb): 1650
- Weight (oz): 0.5
Applications:
- Mainsheet and spinnaker sheet turning blocks on dinghies to 4m (13ft).
- Control lines.
- Cascading vangs.
- Leech lines & cunninghams.
Materials:
- BB Sheave and balls: High compression strength acetal.
- Frame/cheeks: Toughened, glass-fiber-reinforced nylon.

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