[Custom windows, custom doors, residential windows and doors, commercial windows and doors - Jefnik Windows & Doors - Sales, Installation and Service for the GTA, Mississauga, Oakville, Brampton, Etobicoke, Milton, Toronto, Ontario, Canada Jefnik Windows and Doors supplies and installs vinyl, aluminum, fiberglass and wooden windows. We also manufacture our own custom made steel and fiberglass entry door systems including single doors, double doors, doors with sidelites, as well as custom shapes and sizes. Serving Mississauga, Oakville, Brampton, Etobicoke, Milton, Woodbridge, Toronto and the GTA.]