Its closer than you might think - Fitbit did $1.5B in rev last year. Haven't check their filings but presumably thats almost all from their devices. Garmin did $858m in rev last year from their "fitness" segment. Plus some fraction of their $809m "outdoor" segment includes the Fenix line, which is also in the same category. So probably $1B+ total
Fair point actually, it is closer than I thought my apologies.
Garmin makes a lot more money per unit. (Avg selling price of likely over $300) Fitbit sells many more units per year (@~$130/unit), which is scalable.