A "special adapter" is a device or tool that helps connect two things together, even if they are not exactly designed to fit each other. It is like a middleman that allows compatibility between different objects or systems. Full definition
Travel Systems are basic strollers with special adapters that let you snap an infant car seat on top of the stroller seat, making it safe for newborns. (pregnancy-info.net)
Starbucks went so far as to offer special adapters you could plug into your phone to take advantage of this feature, and as long as you could wrap your head around plugging something in to your power port so your phone could charge «wirelessly» it worked okayish. (androidcentral.com)
It looks like some third - party hardware makers are tackling this problem with special adapters, but the whole setup seems pretty cumbersome. (tomsguide.com)