All polyplastic window fittings are available in either a 'standard' screw-on fitting or the more recent variant of the slide-on 'Polyfix' design.

The slide-on 'Polyfix' design are easily recognisable by the deep grove moulded in to the back of the window fitting. It is this that slides over the adaptor fitted to the window.

Slide-on fitting
Supplied as packed pairs