in the humid summers, both the upper and lower parts are opened; in other seasons, only the upper one. the pet’s view gives pets the same opportunity, and all they have to do is wear it around their necks. thanks again for sharing all your hard work! contact apartment security system guys when you need the best services at a minimal rate. carry out an inspection to make sure all of the lights are functioning properly. excited to meet your new ‘creature’! it's the other way round: they choose us. 