On Fri, 13 Apr 2012 07:33:16 -0400, "J. Clarke"
The rings are copper, they should be at least as resistant to mouse pee
as copper pipe, and there's a lot less area exposed to mouse pee.

Don't know about mouse pee, but I've been thinking that the relatively
soft outer shell of PEX would be more apt to be chewed on than copper
pipe.