Leno weaves, like style 1659 photo to the right, have two or more warp yarn locking with each other over a fill yarn. The result is a net type cloth.
Style 1659 is a 1.6 oz/sq yd LENO weave with a 20 x 10 ends/inch thread count that uses the yarn ECG 150 1/0 in the warp and ECG 75 1/0 in the fill.
You can see the two G150 yarn in the warp (up and down) locking over the twice-the-size G75 yarn going side to side in the fill.
A little closer look at the warp yarn locking around the Fill yarn in the LENO weave style 1659 1.6 oz/sq yd fiberglass "Net" cloth.
To the right is a microscopic photo of style 7587 which is a 20 oz/sq yd Mock Leno Fiberglass tooling cloth