Hi Don,
The battery that I ordered (you need three) is made by CSB (China Storage Battery), and the model number is HRL-1234W-F2-FR. The "L" means that it is the premium long-life battery, and the F2, which is very important, specifies the terminals, which match the leads inside the 1050.
I ordered the batteries from Mouser Electronics. Google them on-line and you'll find them. Their service was excellent, very fast, unlike PurePower. Mouser adds "632" to the front of the part number, just in case you need that to order them. The batteries came extremely well-packed, and they arrived in perfect condition.
I assume you have the PDF file with illustrated 1050 battery replacement instructions. It is on the PurePower website. If you have trouble finding it, let me know and I'll be happy to send the file to you. Just provide your E-mail address.
I hope our 1050's keep working!
Regards,
Alan Hayman