White board does not change the small parcel maximum of 450 x 350 x 160 mm outside. This page stays with Royal Mail small parcel boxes, next to crash lock boxes.
Packaging Boxes keeps Royal Mail small parcel boxes apart from an oversized cube. The outside maximum on the changes page is 450 x 350 x 160 mm. The box has to finish under that, tape included.
What this collects
These are the boxes aimed at the Royal Mail small parcel limit.
crash lock boxes is the neighbour on this list. A crash lock box opens into shape and has a peel-and-seal strip. It is still a different range from Royal Mail small parcel boxes.
Before the order goes in
Measure the finished parcel, not the goods alone.
At Packaging Boxes, Royal Mail small parcel boxes does not change the cutoff. Orders by 3pm leave the same day. Under £50 ex VAT the delivery is still available. It is just not the free threshold.