This is the design you need for most vintage and antique letter plates.
Two springs 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 £20 and made from 1.4mm diameter galvanised steel for corrosion resistance and it gives a good recoiling force (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.

Please see my other items.