SUNLU Gen 2 vs. Gen 3 Spool: How to Tell Them Apart
Updated September 22, 2026
The short answer: SUNLU's Gen 2 spool has open, cutout side walls and does not accept a refill coil or reliably fit the Bambu Lab AMS. Gen 3 (2025-) has a detachable, multi-hole side-wall design, accepts SUNLU's own refill coils, and is documented by SUNLU as AMS/AMS Lite compatible. Below is what's actually documented for each, and where the evidence is thinner than we'd like.
Side-by-side comparison
| Gen 2 | Gen 3 (2025-) | |
|---|---|---|
| Side-wall design | Open/cutout pattern to reduce weight | Detachable, multi-hole/porous design with printed weight-scale markings |
| Reported diameter | ~195 mm (community-reported, not a SUNLU spec) | ~200 mm (stated on SUNLU's own store/blog pages) |
| Hub diameter | Not documented | ~55 mm (SUNLU) |
| Accepts a SUNLU refill coil | No | Yes |
| Bambu Lab AMS / AMS Lite fit | Not verified - community reports of fitment issues | Fit documented by SUNLU |
| Durability note | Side walls reported prone to cracking | Marketed as stronger/more reinforced than Gen 2 |
What's solidly documented
- SUNLU's own wiki introduces refill compatibility as a feature specifically of the "third-generation reusable spool system" - implying Gen 1 and Gen 2 don't have it.
- SUNLU's Gen 3 product pages state approximate φ200 mm × φ55 mm dimensions and Bambu Lab AMS/AMS Lite compatibility.
- An independent comparison guide (3DScapers) explicitly scores Gen 2 as "No" for both refill support and Bambu AMS compatibility, and Gen 3 as "Yes" for both.
What's not solidly documented (research gap)
- The ~195 mm Gen 2 diameter figure, and the specific claim that it causes AMS fitment problems, come from a Bambu Lab Community Forum discussion - a community report, not a SUNLU spec sheet or an independently repeated measurement.
- SUNLU has not published a page that names "Gen 1" or "Gen 2" directly and states non-compatibility in those words; this comparison combines SUNLU's Gen-3 framing with an independent reviewer's side-by-side guide.
Because of that gap, SpoolNook's checker marks the SUNLU Gen 2 → Bambu AMS pairing as Not verified rather than a confirmed mismatch, even though the available reports point that way.
Check your own pairing
Use the checker preloaded for a SUNLU Gen 3 spool and SUNLU refill, or pick your own spool and refill directly in the compatibility checker.
