This extension provides you a date picker on product page for selection of delivery date of products.
This extension is specially for managing order delivery date.If you want to add a feature of estimate delivery date of products then you can use this extension.
After installation of this extension one date picker will come on product page, which allows customer to pick a estimate date of delivery.
Suppose that if you are able to deliver your products after 3 days from placement of order then you can set minimum delivery "+3" in configuration, then on frontend customer will be able to select estimate delivery which is more than (current day+3days).
Extract the package in app/code/ directory.
Admin can manage Setting From Store->Configuration->Gaggle Thread->Manage Delivery Date Calendar