You can give yourself 4 extra SIM Cards with this Samsung Galaxy Multi-SIM Adapter - Yanko Design
Buy MAGICSIM Elite - Dual SIM Adapter for your Galaxy S7 Edge
Micro SIM Card Hybrid Double Dual Micro SD Adapter For Samsung Galaxy C7 Pro J2 J2 Core J2 Prime J3 J5 J6 J7 J8 Plus Prime Neo - AliExpress
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SIMore - Convert single SIM Samsung Galaxy S8+ to Dual SIM... | Facebook