Many inexpensive two-spool filament dryers solve the capacity problem but stop at temperatures that are most comfortable for PLA, PETG, and TPU. That is fine until you want stronger moisture recovery, run ABS or ASA more often, or occasionally need to rescue nylon without buying a large premium dryer.
The Comgrow SH02 dual-spool filament dryer fits that middle lane. It holds two spools, lets you print from the box, and offers a 40–70°C setting range. That makes it more flexible than a basic 50°C dual-spool box without pushing every buyer into the cost and bench space of a four-spool or high-end engineering-material system.
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Short answer
The Comgrow SH02 is the best 70°C dual-spool filament dryer for makers who regularly dry PETG or TPU, want two-spool print-from-box feeding, and need occasional extra heat for ABS, ASA, or nylon. Its strongest advantage is not simply that it holds two rolls. It combines two-roll capacity with a higher 70°C ceiling than common entry-level 50°C boxes.
Buy it for a compact two-spool workflow with more temperature headroom. Skip it if you only dry one PLA or PETG spool at a time, need room for four active spools, or routinely process heavily saturated engineering filament that deserves a more powerful premium dryer.
Why the 70°C ceiling matters
Dryer temperature is not a score where the highest number automatically wins. The useful question is whether the available range matches the materials you actually print.
- PLA: does not require a 70°C setting, and excessive heat can soften or deform some spools.
- PETG and TPU: benefit from active drying, especially when popping, stringing, rough surfaces, or inconsistent extrusion return after storage.
- ABS and ASA: make the extra temperature headroom more useful than it is on a 50°C-only box.
- Nylon and some engineering materials: are where 70°C becomes attractive, although very wet nylon may still need longer cycles or a more serious high-temperature dryer.
The SH02 therefore makes the most sense as a step-up from entry-level drying, not as a universal substitute for every professional filament-drying system.
Comgrow SH02 key specifications
- two-spool enclosed dryer with outlets for printing directly from the box
- adjustable 40–70°C drying range
- one-touch presets for nine filament families
- 150 W PTC surround heating with active air circulation
- 3.9-inch touch display with live operating information
- triple-ring sealing design intended to slow moisture re-entry
- support for 1.75 mm and 2.85 mm filament feed paths
- overheat protection plus fan, exhaust-temperature, and mainboard-temperature monitoring
Manufacturer specifications are useful for comparing the design, but a set temperature is not the same thing as proving that the center of a full spool instantly reaches that temperature. Drying still takes time, and room conditions, spool size, initial moisture load, and ventilation affect results.
Who should buy the Comgrow SH02?
- PETG and TPU users with two active colors or materials: you can keep both rolls in one controlled feed workflow instead of swapping a single-spool box constantly.
- makers stepping up from a 50°C dryer: the 70°C ceiling gives ABS, ASA, and occasional nylon users more useful headroom.
- dual-printer benches: two outlets can support a cleaner print-from-box setup when each printer needs a separate dry spool.
- budget-conscious engineering-material users: it offers a middle ground before moving to premium high-temperature equipment.
- people who want drying and active feeding together: the box is easier to justify when the filament stays in the workflow during the print.
Who should choose something else?
- PLA-only beginners: a cheaper single-spool dryer is usually enough.
- four-spool multicolor users: a SUNLU S4-style system better matches four-roll capacity.
- people drying oversized 3 kg rolls: choose a dryer designed around large-spool clearance rather than assuming a two-roll box will fit.
- frequent PA-CF or heavily saturated nylon users: a premium dryer with higher heat, stronger circulation, or documented engineering-filament performance may be the safer long-term buy.
- storage-first buyers: if your filament is already dry and simply needs protection between prints, sealed storage and fresh desiccant may cost less and use no power.
How it compares with the main alternatives
Comgrow SH02 vs Sovol SH01
The Sovol SH01 is the simpler budget choice for two-spool PLA, PETG, and TPU duty. Its lower temperature ceiling is the important limitation. Choose the SH02 when the extra heat range is the reason you are upgrading; choose the SH01 when price matters more and 50°C-class drying already matches your materials.
Comgrow SH02 vs Creality Space Pi Plus
Both target a more polished two-spool experience than the cheapest boxes. The SH02 is compelling when its 70°C range and sealed two-roll workflow line up with your needs. The Space Pi Plus may be the more natural choice for buyers already comfortable with Creality's accessory ecosystem or who prefer its control layout. Compare current price, external dimensions, spool clearance, outlet direction, and warranty support rather than choosing by brand alone.
Comgrow SH02 vs SUNLU S4
The SUNLU S4 wins on four-spool capacity. It suits multicolor users and print farms that would otherwise juggle two separate dual-spool boxes. The SH02 is the more focused choice when you only need two active rolls and do not want a much larger dryer occupying the bench.
Comgrow SH02 vs EIBOS Polyphemus or PrintDry PRO3
Premium dryers make more sense for people who routinely process demanding engineering filaments, larger spools, or very wet material. The SH02 is the value-oriented middle step: more heat than entry-level boxes, without pretending to replace every serious drying setup.
A practical way to use a two-spool dryer
- Confirm that moisture is plausible. Popping, steam, rough extrusion, unusual stringing, brittle filament, or inconsistent flow are better clues than a disappointing print by itself.
- Use the material preset as a starting point. Check the filament manufacturer's guidance and stay below temperatures that could soften the spool or material.
- Give the center of the spool time to dry. The display reaching its target does not mean the whole roll is finished.
- Keep the feed path gentle. Position the dryer so filament leaves the outlet without a sharp bend or excess drag.
- Move dry filament into sealed storage afterward. A dryer repairs the moisture problem; good storage slows its return.
What to verify before ordering
- measure the bench footprint and leave room for the lid, screen, power cable, and filament outlets
- check the diameter and width of the exact spools you intend to use
- confirm that the outlet location works with your printer's extruder path
- decide whether you truly need two simultaneous spools or would get better value from one stronger single-spool dryer
- compare the current listing's included rollers, tubes, plugs, and warranty details because bundles can change
The limitations buyers should understand
The SH02 does not make moisture troubleshooting automatic. A humidity readout describes air conditions inside the box, not the exact moisture content locked inside a spool. A 70°C setting also does not guarantee instant, uniform 70°C filament temperature. Very wet rolls can need long cycles, and some engineering materials remain better suited to higher-end equipment.
It is also possible to blame wet filament for problems caused by retraction, temperature, partial clogs, cooling, or a poor feed path. Drying is most useful when the symptoms and storage history support the diagnosis.
Final take
The Comgrow SH02 is the best 70°C dual-spool filament dryer for makers who want two-roll convenience with more heat than a basic 50°C box. It is especially well matched to PETG and TPU users who sometimes move into ABS, ASA, or nylon and do not want to buy a four-spool or premium engineering-material dryer yet.
The buying logic is simple: choose it because you need two active spools plus meaningful temperature headroom. If you only need one mild-temperature spool or routinely dry the most demanding materials, a different class of machine will make more sense.
Frequently asked questions
Can the Comgrow SH02 dry two spools at once?
Yes. It is designed as a two-spool dryer with print-from-box outlets. Drying time can still increase when the chamber contains more filament mass, especially if both rolls begin very wet.
Is 70°C enough for nylon?
It is more useful for nylon than a 50°C-only box, but the honest answer depends on the nylon, its spool, and how much moisture it absorbed. Occasional nylon users may find the SH02 sufficient with longer cycles. Frequent engineering-material users should compare it with higher-temperature premium dryers.
Can you print PETG or TPU directly from the SH02?
Yes, provided the outlet and PTFE path are arranged without excessive bending or drag. That print-from-box workflow is one of the main reasons to choose a dryer that holds two active spools.
Does a filament dryer replace sealed storage?
No. Active heat removes moisture; sealed storage slows moisture from returning. The strongest workflow is dry first, then store the roll in a sealed container with appropriate desiccant.