Nice quality cotton cord which is a close match to a mint vintage cord I have from 1960, generous hank of 10yds for those larger cranes etc., available in 1mm thick (as Meccano) or a heavier duty 1.5mm thick, 

Hank of approx 9.2 m (10 yds) £1.80

Replica Meccano cord 10 yds Green

SKU: hc3