Digital and Electronic Device Design gosh! Parallel 2 Portable battery case by Appcessory Pte Ltd The Parallel 2 is a detachable 'slide on' Battery Case with a built-in lightning connector. The battery pack glides into a precision engineered grooves on the sides of the Protective case when more power is required. The whole form factor retains the exact length and width of the phone which reduces overall size and bulk. When not mounted, the Phone sits snuggly into a soft polymer case with polycarbonate back. It packs with 2900mAh of juices giving you 1.5X power on the go.