This is truly a stupid question...however...it had occured to me that in my many years of dealing with lighting equipment basic stage lighting I never heard a name given to the knobs on the yoke that tilt the instrument up and down. I know every other term for every portion of the instrument except for the most obvious one the sticks out like a sore thumb. I actually looked a student today and had to say...uhhh i'own'owe. So, what do you call them?