Note 10 - Product Warranty - Changes in Product Warranty Liability (Details) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Aug. 31, 2026 |
Aug. 31, 2025 |
Aug. 31, 2026 |
Aug. 31, 2025 |
|
| Balance, beginning | $ 177,661 | $ 213,929 | $ 225,000 | $ 225,186 |
| Provision charged to expense | 35,089 | 77,334 | 212,569 | 260,709 |
| Less amounts charged-off | (36,229) | (70,713) | (261,048) | (265,345) |
| Balance, ending | $ 176,521 | $ 220,550 | $ 176,521 | $ 220,550 |