Danze, Special tool to remove single handle mixer cartridge cover?

[ejsarge]

Underneath the shower handle I've found this interesting design where there's a cover or shroud encapsulating the cartridge. The threading on it is interesting: the threading isn't required for the handle and there are two flat areas near the end. I'm guessing there's a special tool I should use to get access to the cartridge. (No, I don't think I'm referring to a cartridge puller.)

How would I find this tool? Or can anybody identify the manufacturer?

 

[Marlinman]

You remove with cresent wrench. The long threads have no purpose with this type trim. No special tools for that piece. The trim part behind it will possibly need a strap wrench to remove. Part sheet below.

http://igate.northernplumbing.com/partsbreakdowns/danze/d510021.pdf