Help! which bulb is right for me?

Which of these (http://www.bltdirect.co.uk/cat38_1.htm) bulbs do i need for a 250w hps/mh ballast?

would it be this one?

SON-T High Pressure Sodium (Tubular) Super (Plus) External Ignitor

cmon people, i know you know!

just get 250w HPS or MH bulb like this one : http://www.bltdirect.co.uk/item645.htm

thank you.