Windows stays help keep caravan windows open and to secure them when closed. 
Caravan window stays come in a range of sizes and they will also vary in the length to which they extend. They also come in a Left hand and Right hand side. Therefore when ordering a replacement stay it is important to check that the stay is identical to the stay fitted in your caravan.
Sizes:
Long (Open 445) (315 Closed) 
Medium (Open 370) (230 Closed) 
Short (Open 230) (160 Closed) 
X Short (Open 320) (205 Closed)