OREGON CHAIN FOR CHAINSAW ONLY PITCH 21 THICKNESS 1.5 mm Chain adaptable to models: 639 - 641 - 644 - 650 - 645 - 647 - 651 - 654 The chain is available in the following links: - 57 links: length 33 cm - 61 links: length 35 cm - 65 links: length 38 cm - 67 links: length 40 cm - 68 links: length 40 cm - 73 links: length 45 cm OREGON