In my experience, Mugen makes the best extended batteries (both in size and performance).
Of course this is not useful if your phone does not have a replaceable battery (e.g. iPhones). But in general any popular phone with a replaceable battery will have extended batteries made for it. You just put the extended fat battery in then use the provided replacement back panel that includes an enlarged area to hold the new fat battery.
I *always* get this for my phones because I get sick of having to remember to charge them.
I think you mean Parkfield, rather than Garfield.
(Trivia, there was at one point an actual Garfield, California at one point in history -- it was in the central valley.)
Whitman lost to Jerry Brown, BTW, thus earning Brown the singular distinction of having to clean up the mess left by a B-grade movie actor twice.
Very very occasionally, if the description sounds interesting, I'll paste the description/requirements into Google. Most of these spamming third-party recruiters just copy-paste from public job postings, so Google can usually find the original posting on the employer's Web site.
"Ninety percent of baseball is half mental." -- Yogi Berra