It can be close the window without hold out your hand from window and can be prevent mosquito fly to our room. It is the first choice for modren household. There are many kinds of item for your choice. All manufacture as American factory products, and it can be interchange with American factory product. Recently, we improved on the lock of manual gear, It not only use with plastic steel window, but also applicability are more extensive, more change. Now it can match aluminium door & window profile and heat insulation break bridge aluminium profile, so manual gear used for thousands familys. Our Company offer manual gear accessories, and also offer window screen accessories with manual gear. And provide procuction instructor. Please contact us if you are interesting in manual gear.