3Pairs 18650 Battery Contacts Spring Contact Band Plate 18.5*16MM 16.5*16mm Connector Positive Electrode Negative Box/Power Bank - AliExpress
18650 Battery Terminal Insulators - (20 pcs) Light Blue Paper - BatteryPacks.com
Reprinted the giant battery pack for my xbox controller using an awesome looking translucent filament. Also used 18650 battery contacts for the case this time. : r/functionalprint