Lewmar 50mm Synchro Block – Single with Becket & Cam, Black, 1/4”–3/8” Line
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
Precision-Engineered for Speed and Low Friction
The Lewmar 50mm Synchro Single Block with Becket and Cam is a compact, high-performance block built for sailors who need smooth, controlled line handling in tight spaces. The integrated cam cleat lets you lock off the line instantly without a separate cleat, while the becket provides a fixed attachment point for building purchase systems. The high-density, free-spin plain bearing and self-aligning swivel head keep friction to a minimum under load.
Constructed with stainless steel straps and glass-fibre reinforced cheeks, the Synchro series handles the demands of performance sailing while keeping weight low. The sheave, bearing, pin, and line size are matched for optimum efficiency across the 1/4”–3/8” line range.
Compatible Applications
- Mainsheet systems with integrated cam lock-off
- Vang and cunningham purchase systems
- Control lines requiring quick cleating on smaller sailboats
- Running rigging on performance dinghies and keelboats
- Line sizes: 1/4” to 3/8” (6–8mm)
- Block size: 50mm sheave diameter
Product Details
- Configuration: Single sheave with becket and cam cleat
- Sheave diameter: 50mm
- Line range: 1/4”–3/8” (6–8mm)
- Color: Black
- Bearing: High-density free-spin plain bearing
- Head: Self-aligning swivel
- Construction: Stainless steel straps, glass-fibre reinforced cheeks
- Attachment: Patented shackle post lock
- SKU: 239-29925009
Parts Desk Insights
Best Use Case: The single-with-becket-and-cam is the go-to block when you need a purchase system anchor point and a quick cleat in one unit — ideal for mainsheet systems on smaller boats where space and weight are at a premium. The cam cleat eliminates the need for a separate cleat fitting, keeping your deck clean and your rigging simple. Best suited for dinghies, day sailors, and performance keelboats in the 20–28 ft range running 1/4”–3/8” line.
Other 50mm Synchro Blocks
- 50mm Synchro Block – Single, Black
- 50mm Synchro Block – Double, Black
- 50mm Synchro Block – Triple, Black
- 50mm Synchro Block – Single, Black (29925004)
- 50mm Synchro Block – Double with Becket, Black
- 50mm Synchro Block – Triple with Becket & Cam, Black
- 50mm Synchro Halyard Block, Black
- 50mm Synchro Block – Fiddle with Becket, Black
- 50mm Synchro Block – Fiddle with Cam, Black
Other Synchro Block Sizes
- 60mm Synchro Blocks – 5/16”–3/8” Line
- 72mm Synchro Blocks – 3/8”–1/2” Line
- 90mm Synchro Blocks – 1/2”–9/16” Line
Pair It With
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.