what tunnel extension will fit a phazer 2?

[JordanHall488]

i really need a tunnel extension for my phazer 2. im going with 136. can someone direct me to a place were i can find one? or will one fit from like a vmax/srx or something?

 

[PZ 1]

I think Hartmann Inc. would have one. Do a web search.

 

[JordanHall488]

are all tunnels the same width?