Forks people actually search — button count, battery class, housing, cartridge stamp, filter size.
Where to find the part number · Learn-button eras · HVAC filter size
| 81LM | 893MAX | |
|---|---|---|
| Buttons | 1 | 3 |
| Status | Discontinued | Current |
| Must verify | Opener learn-button color (white/DIP exceptions) | |
Full 81LM → 893MAX notes · 890MAX (1-button) · 895MAX (panel)
| Class | Example SKU | Notes |
|---|---|---|
| CP | — | Compact / lower Ah end of M18 |
| XC | 48-11-1850 (~5.0 Ah) | Common all-around XC5.0 |
| HO / FORGE | See M18 map | Higher output packs; still M18 rail only |
| Hard stop | M18 ≠ M12. DeWalt 20V MAX is a different rail. | |
Filter numbers are not cross-compatible across housings. Use the table:
1225 vs 1255 vs 1200 — stamp on the old cartridge wins.
| Question | Where |
|---|---|
| Will it slide in? | W × L × T on the frame |
| How fine is the media? | MERV / MPR guide |