Thetford SD2 Dust Cap is a lock cover for exterior toilet door  
 
Thetford dust cover which fits around the lock barrel and covers the lock on the outside of a No 3 Thetford toilet door
This helps to prevent dust from entering the lock
Diameter of Cap: 29mm approx (outside) 25mm approx (inside)
Diameter of attaching Loop: 29mm approx (outside) 22.5mm appros (inside)
Colour: Beige
Genuine Thetford Part