Hi iv been a spark for 6 years now and spent 3 of them testing for a company so i know how to test. But i haven't got my 2391 yet and want to do this in october. All sparks i know that have done it say it's really hard and require you to know the regs inside out( i know parts of it but it's impossible to know everything written in there). All i want to know is what the exam is all about , can't find it on internet. cheers