Transair (I think it was) once sent out a 'Marine' catalogue with their 'Aviation' catalogue.
You'll notice I wrote 'once'.....
Because after quite a few people noticed that the same items were being sold at a lower price in the 'Marine' catalogue, Transair didn't do it again........
For example, the same Leatherman was £5 cheaper in the 'Marine' catalogue.
(Apologies if it was some other company!).