Replacement spring for traditional vintage and antique letterboxes, not suitable for modern styles.
They fit to the left hand hinge only,suitable for rods up to 5.5mm diameter but work equally well with smaller diameter rods,this type of letterbox is still manufactured.

The springs are exactly the same as items costing £14 and made from a 1.4mm diameter galvanised wire for corrosion resistance and give a good recoiling force for the length of the coil (a firm feel but won't take the postman's fingers off).

There is a series of pictures showing how easily the spring is fitted.
Fits most vintage and antique letter plates.