Tools of the Trade

A survey published in the 2013 book Canadians and their Pasts by a team of seven prominent Canadian researchers found that while Canadians engage most with the past by looking at old photographs (83%) and watching historical movies on TV (78%), third most common was passing on heirlooms (74%). That’s well ahead of creating family trees (20%).
What kind of heirlooms?
Perhaps medals. Many of us have them from ancestor’s war service. Issued by the million they’re unique only for the name inscribed on the rim.
I have a silver tea service inscribed as a gift from his parishioners to my great grandfather in 1894 when he left the Lancashire parish where he was vicar. While not a tool of the trade it speaks to his calling.
As a kid growing up I remember curiously play with a slide rule my father had in his desk drawer. I didn’t understand how to use it at the time. He perhaps used it as an engineer plying the seas with the New Zealand Shipping Company, or perhaps while training. There was also a wood and brass mariner’s telescope perhaps used to scan the horizon in the spare moments he wasn’t in the engine room on voyages between the UK and New Zealand.
From my mother, she treasured a book on radio engineering that belonged to her brother killed in a flying accident with the RAF.
As a former meteorologist I'd choose to hand down a geostrophic wind scale or tephigram (Google them!).
What ancestor’s tools of the trade handed down do you value and what will you be handing down?