i over ordered... how do i change quantity in cart?

You can adjust the quantity in the gray box under "Quantity". Once the number is adjusted, you can click out of this box and the shopping cart will be updated.

Will this ribbon work on a Zebra GK420T

Our TR2182ZC can be used on the following printers: Zebra® 110Xi4, Zebra® 140Xi4, Zebra® 170Xi4, Zebra® 220Xi4, Zebra® 105SL Plus, Zebra® ZM400, Zebra® ZT220, Zebra® ZT230. For the Zebra® GK420T, you'll need a thermal transfer ribbon with a 0.5" core instead. Below is a link to our TR2181 which is compatible with your printer model. https://www.onlinelabels.com/products/tr2181