two ply meaning in Chinese

二层胶合板
两层

Specification for two ply cotton fabric interlayered with polychloroprene for liferaft packs
救生艇包用氯丁橡胶夹层的双层棉织物规范
Conveyor belts with textile plies for coalmining - permanent joints for belts with one or two plies ; dimensions , requirements , marking
煤矿用织物叠层输送带.单层或双层带的永久性连接接头
Conveyor belts with textile plies for coalmining - part 2 : rubber - belts with two plies for underground applications ; dimensions , requirements
煤矿用织物叠层输送带.第2部分:井下用双层橡胶输送带
Conveyor belts with textile plies for coalmining - part 4 : rubber - belts with two plies for above ground applications ; dimensions , requirements
煤矿用织物叠层输送带.第4部分:露天用双层橡胶输送带