Apple iPhone Smart Battery Case review: Pretty good, if you need the boost - CNET
Best Buy: Apple iPhone XS Smart Battery Case Black MRXK2LL/A
iPhone XS Smart Battery Case Review | iMore
Tested: Using the iPhone XS Smart Battery Case on the iPhone X | AppleInsider
Amazon.com: Battery Case for iPhone XS Max, Enhanced 10000mAh Ultra Thin Portable Protective Power Smart Charging Case Compatible with iPhone XS Max (6.5 inch) Rechargeable Extended Battery Charger Case (Black) : Cell