Which cable

Bell wire is typically 18 or 20 gauge solid core.

Should be fine for runs under 20'.

I use 12' runs of 26 gauge solid core speaker wire and have been doing so for 15+ years.

DeKay

Mark Twain would be proud!

Be sure to have he who shall not be named check your new purchase for "directionality" before use.

The wire on the link I gave is covered in clear plastic.  No worries.  20 gauge is not enough gauge on its own as the OP would use it. 

I just rewired my doorbell with a double run of Acoustic Zen Satoris and getting much better tonality and soundstaging. There are some people who say they can’t hear a difference between doorbell cables, but with proper setup and assuming the doorbell has decent resolution I’ve found that cables can make a huge difference. If you’ve invested in a good doorbell you really should consider demoing some better cables. I only have 17 rings on them at this point, but even my wife noticed the doorbell sounds better. I’ll report back once the cables are more fully broken in.