The complete guide
What a corner piece set is for
What a set is
Four corner pieces and two wind clips. That is one screen.
It is worth being blunt about it, because the number is the thing people get wrong on a first order. Building three small screens out of one large one means three sets, not one.
What the corners do
They make four cut lengths of PVC frame into a frame.
That sounds obvious and it is the entire job. The flexible PVC profile is sold by the metre and cut to each side of your window. Until the corners go in, you have four lengths of profile and a plan. They push in with no tools at all.
What the wind clips do
This is the part that gets left in the packet.
The reason a magnetic window screen looks slim rather than bulky is that its frame is flexible PVC instead of rigid aluminium. On a small window, flexible is only an advantage. On a large panel, a strong gust will move a flexible frame, and a frame that moves is a screen that stops sitting flush.
The two wind clips in every set are the answer to that. Rule of thumb: if the panel is a metre and a half or more on its long side, fit them.
When people buy these
Three cases, and they cover nearly every order.
Building a screen from scratch for a window no stock size fits. Splitting one large screen into two or three smaller ones, which is usually the cheapest way to do a whole house. And replacing a corner that snapped, on a screen where everything else is perfectly good and a whole new screen would be absurd.
Colour
Black, brown or white, all the same price.
The corners are visible on the finished screen, which is why there is a choice. Match them to the frame colour. Mixing them looks exactly like mixing them.
The rest of the kit
Corner pieces on their own do not make a screen. You also need PVC flyscreen frame by the metre, a sheet of replacement mesh in the grade you want, and magnetic strip by the metre.
All four are sold separately here, and if you have not assembled one before, order them together so the whole kit is in front of you rather than arriving in instalments.