[sdiy] LED panel mounting?

[Ordeish at aol.com]

 Hi all, I am putting the finishing touches to my mouser order. I was going to use 3mm leds with a T-1 single piece moutning (606-CMP100).
 I realized though that I do not know the size of this mounting. What does T-1 stand for? Is it for 3mm? How big of a hole do I need in the face plate for this mounting?

 Any help is appreciated. Also thankyou to everyone who helped me out with my questions about resistors.

 thankyou

Edward