traditional british wedding gift?

i want to get a gift for someone from the states who is getting married next month. i'm going to have to post it to them so i don't want it to be too heavy. i'd like to send something traditionally british, but after thinking about it, i don't know what will fit the bill!! i was thinking of a quaich, but that's pretty heavy to post and may cost the same again in stamps!

i'm looking in the region of £30/£40 including postage and wondered if anyone on here had some suggestions?!