Treat WINDBAR D91 vs Lost Mary slim bar as two checks that must both pass.

Form check.

Step 1. Write 20 × 82 × 10 mm. Width 20 mm is about a finger. Thickness 10 mm is the card-like axis. Height 82 mm is the long axis that will stick from a shallow coin pocket.

Step 2. Put a credit-card-thick object next to a ruler at 10 mm. If a Lost Mary OS5000 or Geek Bar 5000 listing photo looks like a rounder bar, that photo is not proving D91.

Step 3. Open the complete 3:4 catalog front on this site, not a banner crop and not a competitor lifestyle still.

Voltage check.

Step 4. Read 4.4 V as peak flavor drive, not as a claim that every puff is locked at 4.4 V in every market.

Step 5. If you want the arithmetic, open the WINDBAR ohm’s law calculator and enter 4.4 V plus the ohm printed on your insert. Packaging limits win over pure math. Do not use an off-site calculator.