Our house is on Lissa Links. We have three sliding patio doors, two ordinary doors, a kitchen window and two bathroom windows in total. The screens which are a fine mesh in PVC frame are fitted to the outside of the property for the patio doors and are of the slide type, similar to the patio doors themselves. The sliding screen seals against the door frame to stop the blighters getting in through any gaps. The two ordinary doors on the top floor balconies open outwards threrefore the screens are fitted on the inside of the door frame opening inwards. The kitchen window and one of the bathroom windows have the screens fitted on the outside and are fixed i.e. they do not open. These windows open inwards so the outside of the glass can be readily cleaned. The second bathroom window is round (like a porthole) so we have not has this one done yet. I am considering fitting a mesh on the inside for easy access but have not yet fully decided. In total, cost me about £240 fitted. The fine mesh can easily be replaced should it get damaged which is a possibility I'm afraid. The mesh is very fine and not easy to see with the result we nearly walked through it on a couple of occaisions. I intend to make a stencil and use it to paint a pattern of some description on the screen to make it more obvious. I believe they will 'eventually' pay for themselves as we prefer to have the windows / doors open rather than having the a/c on, especially at night. Hope this helps.