Measure before you open the range
Pick the bag by the goods, with a little extra for the seam, not by the carton size you used last time.
Grey mailing bags are for soft goods that do not need a rigid wall. The page for Mailing bags is where Wholesale Packaging shows that line.
The published limit, if there is one
The category calls them shoe bags or grey mailers. They are opaque, European made from a blend of recycled film, and described as 100% recyclable.
A carton is for goods that must not be crushed. A mailer will not do that job.
Write the size down
Reorder the size that ran out. A larger bag is not a kinder fit.
TradePro at Wholesale Packaging, for trade businesses, starts at 5% off and goes up to 10% when you spend over £1,000 a month, and it adds BACS. It does not change which Mailing bags you needed.
Open Mailing bags when you already know this line. Bags are pack quantities. Read the count on the product before you assume a single bag. Wholesale Packaging will still dispatch an order placed by 3pm on the same day.