What do I use to join flourescent fixtures?

[Notch1988]

I picked up a few 8' long, 4 bulb T8 fixtures and I'd like to utilize the knockouts on the end to join them. However, I'd like the option to space them apart up to 6" as needed. What do I use the create the spacing and allow the wire to pass through?

 

[StumpjumperDave]

Threaded *******...

 

[CadillacJack]

EMT conduit & connectors.

 

[1/2 Cup]

EMT conduit & connectors.

Endorsed

 

[Notch1988]

EMT conduit & connectors.

That's perfect, thank you.