2.Flo™ Ventilation System:

This is our most effective tent ventilation system yet, and uses multiple airflow paths working together to help reduce condensation within the tent.

  1. Full-width ridge ventilation
  2. Perimeter airflow around the entire fly
  3. Intentional vestibule heights that maximize airflow while offering full protection from the elements.
Trekking pole tent with ventilation system diagram on a black background

Why Condensation Happens In Ultralight Tents

Before explaining 2.Flo™, it helps to understand why condensation happens so easily in lightweight shelters.

Every night, your body releases moisture through breathing and perspiration. In a small enclosed tent, that moisture builds up quickly. When warm humid air hits the colder tent fabric, it condenses into water droplets.

Ultralight tents often make this worse because they tend to have:

  • Low interior volume

  • Limited venting

  • Tight wall clearance

  • Minimal airflow

  • Fabric that sags when wet

When the air inside the tent can’t circulate, moisture has nowhere to go.

That’s exactly what the 2.Flo™ system was built to reduce.

Full-Width Ridge Vents

The Cirq uses full-width ridge vents on both sides of the tent, located at the highest point of the shelter where warm, moist air naturally rises.

This allows humid air to escape instead of collecting at the ceiling.

Because the vents run across the ridge rather than being small openings, they allow more air to move without requiring the door to be open.

Benefits of ridge ventilation:

  • Releases warm humid air before it condenses

  • Improves airflow even in light wind

  • Works in cold conditions without opening the tent

  • Maintains weather protection while venting


Full Perimeter Airflow

Airflow can enter the Cirq from any direction beneath the fly of the tent. This allows cooler air to enter low, and then the full-width ridge vents can expel warmer air and moisture. 

This creates natural convection flow through the shelter.

The vestibules (especially the rear vestibule) were designed to assist with airflow. Rather than pitching your tent with the fly all the way to the ground, the rear vestibule is raised to allow more air to enter the tent. 


Why Interior Space Matters for Ventilation

A larger interior volume reduces how quickly humidity builds up.

More space means:

  • Less moisture concentration

  • Less contact with tent walls

  • Easier airflow

  • More comfortable sleeping

In many ultralight tents, condensation feels worse simply because the walls are closer to your face.

The Cirq’s geometry helps prevent that.




NP Shield™ Fabric

This custom-built fabric has been optimized for lower moisture-induced stretch, improved seam strength & tear resistance, and longer-lasting waterproofness.

NP Shield fabric with water droplets and text highlighting features

What it is: 15D nylon / 50D polyester 3x2 ripstop Sil/PeU fabric 
Waterproof Rating: 2,000mm hydrostatic head 

Sil / PeU (poly ETHER urethane) is stronger and much more resistant to hydrolysis degradation compared to standard PU (polyurethane).  Silicone on the outside, PeU on the inside.  Bi-component 3x2 fabric reduces fabric stretching from moisture while maintaining superior seam strength and tear resistance from the stronger molecular structure of nylon. 

Result: Better pitch stability in wet conditions, less fabric sag overnight, & longer lasting waterproof performance.

 

Cirq Tent Pitching Instructions:

 

Cirq Benefits & Features:

Cirq Design Story: