The Harken 29mm Double Traveler Block, Part No. 353, features a sheave diameter of 29 mm (1 1/8 in) and a maximum line diameter of 8 mm (5/16 in). With a maximum working load of 150 kg (330 lb), these Low-friction Carbo Air blocks are ideal for small boats and offer a combination of lightweight, strength, reliability, and affordability. These blocks are designed to work seamlessly with the Harken Big Boat blocks, providing high working loads for safe and efficient trimming.