The 20mm Plain Bearing Double Block is perfect for take up systems or those that do not require friction reduction. For optimal results, we recommend using the Dynamic block collection instead. This bearing block is crafted from recycled plastics. Featuring a Swivel Hook, this block easily attaches or removes and swivels to align with changing pulling forces. Please note that the swivel cannot be locked. The acetal sheave rotates around the central axle in a plain bearing, which has a long lifespan and requires minimal maintenance. This block also includes a Becket hole to be used as a tying off point.