we have 4 types of RO modules:
1-Plate and frame
2-Tubular
3-spiral wound
4-Hollow fibre
3 is a variation of 1
4 is a variation of 2
In the field of water desalination, 3 and 4 are widely used
modules. 3 is widely spread in world and also has a numerous manufacturer, on the other hand,4 has a few manufacturers,including Dupont , because it has high technology for manufacturing.
Currently, 1 is used only in labs.
2 is used in waste water treatment and juice concentration.
In your country,Hollow fibre is very common (!)