Here's another OzReminder, Credit to urbancartel for the original post

With eBay Guaranteed Delivery, you can search for items that will arrive by a specific date, including the next 1-2 days. If the item you bought doesn't arrive by the guaranteed delivery date, we'll make it right.

Update August 2020

We’re Temporarily Disabling eBay Guaranteed Delivery

Sellers and carriers may be facing new challenges in fulfilling eBay orders and, so we want to give them time to do this safely and securely to ensure you can still shop on eBay with confidence. With this in mind we are temporarily disabling eBay Guaranteed Delivery.

This means you will no longer see eBay Guaranteed Delivery dates on site. Instead you'll see an estimated delivery date which is calculated based how long a seller takes to handle an order and their chosen carrier. You'll still receive all your items safely and securely - they just might take a little longer to arrive.

The Guaranteed delivery filters (e.g. for 3-day delivery) will still be visible onsite, however these won't return any search results while the program is disabled. If you have any eGD items which were ordered previously, you will still be able to claim a postage cost refund, $10 coupon or return if that item is delivered late.