A double jogging stroller has enough space for two young ones to ride, typically side by side, while a parent jogs or walks behind. Since it is a jogging stroller it needs a few extra features from a regular stroller such as larger wheels that are air filled to absorb bumps, a large soft handle for easy grip, and a wheelbase that is easily maneuverable, typically with three wheels.
A double jogging stroller can be found wherever strollers are sold and come in a few different styles and levels of quality. There are a lot of low quality knock-offs that are not really designed for the rigors of running with children in tow but still look good. They may not last nearly as long but they are better on the wallet.
A double jogging stroller should also have secure attachments and buckles for the babies or toddlers riding inside. These should always be used as the frame of the stroller can protect them in case the jogger loses control of the strolled or has to make a quick stop or turn. These strollers can get up to quite the clip even on level ground and many models include a handbrake to aide braking.