Size:

7mm: length 7mm, width 11mm, hole 4.5mm, weight about 1.85g/piece

13mm: length 13mm, width 11mm, hole 4.5mm, weight about 2.9 grams/piece

20mm: length 20mm, width 11mm, hole 4.5mm, weight about 4.1g/piece

Note: The size and weight are measured manually, so there will be some indirect measurement errors.