The common options
Mesh is described by strands per inch (for example 18x14 means 18 strands one way and 14 the other). More strands per inch means smaller openings, which blocks smaller bugs but also lets through slightly less light and airflow.
Standard 18x14 fiberglass
The most common screen on Florida pool cages and porches. Flexible, affordable, and easy to install, with good visibility and airflow. It keeps out mosquitoes and most flying insects but not the very smallest gnats.
20x20 no-see-um mesh
A tighter weave made to keep out tiny biting midges ("no-see-ums") that are common near Gulf-coast water and marshes. The trade-off is a little less airflow and visibility. Popular in waterfront areas.
Heavy-duty / "Super Screen" type
Thicker, stronger screen sold under names such as Super Screen. It resists tears and punctures better than standard fiberglass, and it is often used on lower panels, high-traffic areas, or whole cages where durability matters. It usually costs more.
Pet screen
A heavy, vinyl-coated polyester mesh made to resist claws and paws. It is much tougher than standard screen but thicker and less see-through, so it is often used only on the lower panels or doors where pets can reach.
Solar and privacy screen
A tighter, denser weave that blocks more sunlight and heat and makes it harder to see in during the day. Good for west-facing walls or for privacy from neighbors. It reduces the view out and airflow, so many owners use it only on selected walls.
Colors
Charcoal or black screen is the most common because it's easiest to see through. Lighter colors such as gray are also available.
Mix and match
Many lanais combine types: standard or no-see-um on the roof and upper walls, pet or heavy-duty screen below the chair rail, and solar/privacy screen on one side. Ask your pro to explain the options.