Harken 40mm Carbo Double Block Fixed Tracking_Boardfy Also available in a centre

Also available in a centre zip option

Fixing Hole Centers 57 mm Length  194 mm Thickness  2 mm Weight  37 g

Machined 'Gill Grip' provides extra grip

Breaking Load 275 kg Length  38 mm Maximum Line Size  5 mm Sheave Diameter  16 mm To Suit Shackle Pin  - Weight  15 g

the Zhik range may be a better fit

Harken 40mm Carbo Double Block Fixed Tracking_Boardfy Also available in a centreLow friction Carbo Air blocks are lightweight, strong, reliableand affordable. Companions to the popular Harken Black Magic block line, these small, compact blocks have very high working loads for safe, easy trimming. Sheave 40 mm Length 89 mm Weight 80 g Shackle Pin 5 mm Maximum Line 10 mm Maximum Working Load 440 kg Breaking Load 1080 kg