EDR1RXD1 vs EDR2RXD1
Both are Whirlpool refrigerator cartridges, and they are the pair most often mixed up.

Short answer
Different housings — not interchangeable.
Filter 1 and Filter 2 look alike and sit in similar positions, but differ in length. Confirm the code on the old cartridge.
| Specification | EDR1RXD1 | EDR2RXD1 |
|---|---|---|
| Brand | Whirlpool | Whirlpool |
| Housing | everydrop Filter 1 housing | everydrop Filter 2 housing |
| Rated life | 200 gal · 6 mo | 200 gal · 6 mo |
| Filtration | Carbon block | Carbon block |
| Certification | NSF/ANSI 42, NSF/ANSI 53 | NSF/ANSI 42, NSF/ANSI 53 |
| Installation | Twist-in, quarter turn | Twist-in, quarter turn |
| Refrigerator models listed | 0 | 0 |
| Also sold as | W10295370A, FILTER1, P8RFWB2L | W10413645A, FILTER2, P9WB2L |
What they share
Both are certified to NSF/ANSI 42 and NSF/ANSI 53. That covers the same basic contaminant set, so filtration performance is not the deciding factor between them.
Where they differ
- Fit. Not interchangeable with Filter 4 / UKF8001.
Which one do you need
This is not a choice — it is a lookup. The refrigerator decides. Check the number printed on the cartridge in the housing, or look up your refrigerator model. If both numbers appear on your old cartridge, the housing accepts the newer of the two.