1, 2, 3 easy and simple With the WINBAG it doesn’t get any easier. Window fitting is done quick, effective and precise – and only by the means of 1 person and a little bit of air… The WINBAG is invented for professional fitting of both windows and doors. The WINBAG acts like an extra person on the building site because the fitting is now done by one person – also by large window sections. It applies on both new build and renovation tasks.