2-4 Day Delivery is for Qxpress courier door-to-door deliver, where we ship every business day.  Delivery is guaranteed against loss and you can track your package online. 
 
For Normal Mail, we ship within 4 business days, and Singpost takes 2-4 business days after that to deliver.  Buyer bears the risk of loss or damage during transit.  The post office handles a much higher volume than courier companies, so the risk of damage in transit is higher. And without tracking, the risk of loss in transit is higher also.
Qxpress: Safe delivery of your package is guaranteed.

FREE UPGRADE FROM NORMAL MAIL TO QXPRESS
WITH PURCHASE OF 3 OR MORE ITEMS FROM THIS LISTING IN YOUR CART
Just select and pay for Normal Mail shipping, and if there are 3 or more items from this listing in your cart, we will send your purchase to you by Qxpress at no extra charge.
With Qxpress, safe delivery of your purchased items is guaranteed.

Most of the products we carry are in the same Shipping Group.  Combine your purchases across our many listings into one cart to enjoy greater savings on shipping cost.  See our Packaging and Shipping Details at the bottom for more information.  Visit our Mini Shop to see our full range of product listings.