This spring is made from 1.6mm diameter wire, giving even heavier letter plates a firm feel.  The spring can only be fitted to the left hand hinge of the letter plate as shown in the additional photographs.  It is suitable for some of the heavier Carlisle Brass Letterplates e.g. Model M36H and M36S.  It will also fit other makes - see additional photograph for full dimensions.  The spring is intended to be fitted without modification.  For fitting instructions please read our guide on 'How to fit a letter plate spring'.