Don't know if anyone's suggested this before but over a 21yr period I've lost two magnets after Aralditing them on the diff flange, so I cleaned and degreased the area to glue them back on, with Maplins having took a dive (a ready available cheap source for spares) I wanted a method of security so hit on the idea of a narrow band of 4" dia heat shrink, It works well and still reads through it...Time will tell! Regards Steve