Bi-fold means when closed, the vents create a smooth line and when opened, it forms a stack that moves to the side. Also, it is possible to add an option to integrate a side-hung door to pass through without having to always open the entire stack. Fold and open up with bi-fold doors to maximise the space area that you need. The entire system is supported by a level threshold which increases the ease of entering and exiting. Customise and decide whether to fold the vents inwards or outwards and move them in one direction or both left and right, just like a curtain. Choose whichever opening type, the vents will glide silently on roller carriages guided along tracks at the top and bottom.