uPVC Windows, inc Double glazed glazing, Handle, Cill and Locking mechanism. PVC-U casement windows are the most popular style in the UK. They are characterised by outward opening vents which are combined with fixed panels (lights). They are available in a huge range of styles and colours. The profiles are slim, but strong and insulating. When combined with high quality glazing, they create a thermally efficient window which is robust and easy to maintain and will look good for years to come. Specification. Toughened Safety glazing included. OA product U Value 1.3W/mK. Background trickle ventilation. Espag locking system. White handle. uPVC Cill included (cill is included in the OA product height). Product viewed from the outside. 10 Year Product Warranty. Product is delivered by single person to kerbside only, w/c delivery slot and on day live tracking are sent via email. Crystal Direct Top Opening Window Clear Glass in White Size: 610mm x 1040mm