Sometimes used as a workaround size for printers that don't natively support A7 dimensions. Other Potential Matches
How small is A7? Standard A7 paper size is 74 mm x 105 mm - or 2.91” x 4.13”. A7 Format | A7 Paper Size & Uses | A-Series Paper - Adobe A77zip
If you are printing cards, the standard A7 envelope fits a 5" x 7" card. Sometimes used as a workaround size for printers
Many handheld "inkless" printers use thermal paper rolls or folded sheets. Standard sizes for these are 8.5" x 11" (US Letter) or 8.3" x 11.7" (A4) . A7 Format | A7 Paper Size & Uses
Measures 74 mm x 105 mm (roughly 2.9" x 4.1"). It is commonly used for mini postcards, pocket-sized flyers, and A7 binder notebook refills.
If you tell me the (e.g., Polaroid, Phomemo, or HP), I can find the exact product link and current prices for you. A7 Format | A7 Paper Size & Uses | A-Series Paper - Adobe