The specialized tools included in your kit were perfect for the job, as were these instructions. The old battery came out just as you described and the new one went in without a hitch. I calibrated the new battery as you instructed and my trusty old iPhone 4 fired up like it was brand new.
I'm especially pleased because I'm 80 years old and I worried that I might not have the manual dexterity to take on a job like this. Apparently I did.
Thanks so much for a wonderful product and for the tremendous cost savings!