A small piece of accessory that may not always be on your mind, but comes in handy when required! 

Perfect for pregnant ladies. It's common for your underbust to expand by 1 size, and extenders are useful to help extend the wearability of your current bras. 

Also perfect for ladies with a wider underbust. This allows you to find a better bra cup fit without having to put up with the discomfort of a taut underband.