None. Be yourself and you will be okay.
Sigiloso
Be prepare to travel 60% of the time. This is an on-the-road job. You will work from 8am to 8pm every day. The first half of the day will be a service call at a customer site, the second half will be checking emails, customer communications, and paperwork. This is basically a job where you go from customer to customer and fix their instruments by swapping parts. DO NOT EXPECT AN ENGINEERING JOB. Only some problem solving, but as you get more experience, you will do LESS problem solving.