What “fits” means
Width and thickness can match while voltage and battery type still differ.
We label those cases clearly: same size but different type, or not a substitute.
Common traps
CR2032 vs CR2025 — same width, different thickness.
LR44 vs SR44 — same size family, alkaline vs silver oxide.
Polar H10 wants CR2025 — not CR2032.
Simple rule
Use the exact code from the manufacturer when you can. Only treat another name as the same battery when we mark it as the same battery or also sold as.