Re: OT: Converting miles/km

I was more than a little surprised, just this morning, to find that in
my local branch of Halfords, for a mere £3.99, I can buy a handy guide
to stick on my windscreen:
 
<https://www.halfords.com/motoring/travel-accessories/travel-equipment/speedright-safety-device-181812.html?stockInventory=undefined>
 
I can't help wondering who, in the 21st century, is expected to buy this
"safety device".

 
Classic cars without dual display?