30W vs 40W CO2 Laser: Which One Should You Buy?
A 40W CO2 laser tube and two 20mm ZnSe focus lenses rated 30W to 100W, compared on what each listing states about power, size and support.
On this page
Top picks at a glance
As an Amazon Associate I earn from qualifying purchases.
- 1
Cloudray 20mm CO2 Laser Lens9.5/10View on Amazon - 2
40W Laser Tube 720mm Dia.50mm9.5/10View on Amazon - 3
20mm CO2 Laser Lens9.5/10View on Amazon - 4
GWEIKE G2 Pro 30W Fiber Laser Engraver with 3D & DeepView on Amazon - 5
GWEIKE G2 Pro 30W Fiber Laser EngraverView on Amazon - 6
Longer Laser B1 30W Laser Engraver Cutter with Auto Air AssistView on Amazon
When a CO2 laser starts cutting signs or leather patches weakly, the fix is often a part, not a new machine: a tired tube or a cloudy lens. The 30w vs 40w co2 laser question usually means choosing between replacement parts rated for those power levels. We compared three listings, two 20mm ZnSe focus lenses rated 30W to 100W and one Cloudray CR35 40W tube, on what each listing states about power, size, coating and support.
LaserEngraveHQ earns a commission from purchases made through these links, at no extra cost to you. Read our affiliate disclosure.
Verdict: the Cloudray CR35 40W tube is the pick if your 40W machine needs a new tube: it states 40W rated power with a 45W max, a 720mm by 50mm size and a 4-month replacement policy. The two 20mm ZnSe lenses are the pick if your optics are due for replacement: both are rated for 30W to 100W machines with 50.8mm focal length and a stated transmittance of ≥99.5%. Match the part to the job, not the wattage alone.
Machines on the list
| # | Product | HQ Score | Buy |
|---|---|---|---|
| 1 | 40W Laser Tube 720mm Dia.50mm | 9.5/10 | Buy on Amazon |
| 2 | Cloudray 20mm CO2 Laser Lens | 9.5/10 | Buy on Amazon |
| 3 | 20mm CO2 Laser Lens, 50.8mm Focal Length | 9.5/10 | Buy on Amazon |
40W Laser Tube 720mm Dia.50mm
A 40W CO2 laser tube, 720mm by 50mm, with preconnected cables, a metal head and a stated 4-month replacement policy.
Pros
- 40W rated with 45W max, per the title and bullets
- Preconnected high- and low-voltage ends with connector included
- Nano gold catalyst coating; maker claims TEM00 beam mode
- 4-month replacement policy is stated
Cons
- Spec table says 35W rated against the title's 40W
- 720mm length needs a machine with room to spare
- No laser class or FDA statement for the tube
- Tubes are consumables; listing warns storage attenuates power
Cloudray 20mm CO2 Laser Lens
A 20mm PVD ZnSe CO2 focus lens with 50.8mm focal length, rated for 30W to 100W machines.
Pros
- Rated for 30W to 100W CO2 machines
- ≥99.5% transmittance is stated
- Double-sided solid coating, wiping resistant
- Model and 2.6mm thickness are stated
Cons
- No warranty term is stated
- Single lens only
- No work area or material list is stated
- Only one focal length, 50.8mm, is offered
20mm CO2 Laser Lens, 50.8mm Focal Length
A 20mm PVD ZnSe CO2 focus lens with 50.8mm focal length, rated for 30W to 100W machines.
Pros
- Rated for 30W to 100W CO2 machines
- ≥99.5% transmittance is stated
- Double-sided solid coating, wiping and high-temperature resistant
- 0.02 kg listed weight
Cons
- No warranty term is stated
- Thickness is a 2.0 to 2.2mm range, not a single figure
- Single lens only
- No work area or material list is stated
Other machines to compare
GWEIKE G2 Pro 30W Fiber Laser Engraver with 3D & DeepCheck price on Amazon
GWEIKE G2 Pro 30W Fiber Laser EngraverCheck price on Amazon
Longer Laser B1 30W Laser Engraver Cutter with Auto Air AssistCheck price on Amazon
Side by side
| Spec | Cloudray CR35 40W Tube | Cloudray 20mm Lens | CNCOLETECH 20mm Lens |
|---|---|---|---|
| HQ Score | 65 | 59 | 58 |
| Type | CO2 laser tube, 40W rated | CO2 focus lens, 30W to 100W | CO2 focus lens, 30W to 100W |
| Power | 40W rated, 45W max (title and bullets) | Compatible 30W-100W | Compatible 30W-100W |
| Size | 720mm long, 50mm outer dia | Dia 20mm, FL 50.8mm | Dia 20mm, FL 50.8mm |
| Thickness | Not stated | 2.6mm | 2.0-2.2mm |
| Coating | Nano gold catalyst | Double-sided solid coating | Double-sided solid coating |
| Transmittance | Not stated | ≥99.5% stated | ≥99.5% stated |
| Warranty | 4-month replacement stated | Not stated | Not stated |
| Cables | Preconnected, metal head | Not applicable | Not applicable |
Specifications are manufacturer rated, as published on each listing and collected 21 October 2026.
30w vs 40w co2 laser: what the listings actually compare
One side of this comparison is the part that makes the power: the Cloudray CR35, a 40W CO2 laser tube. The other side is the part that focuses it: two 20mm ZnSe lenses rated for machines from 30W to 100W. They are not two machines, so there is no overall winner; the right pick is whichever part your machine needs. The sections below go through power, size, optics and support using only what each listing publishes.
Power ratings and the fine print
The CR35 title and bullets call it a 40W tube with a 45W maximum, while the spec table lists 35W rated and 45W max. We trust the title and bullets, so read it as 40W rated with a 45W max. Both lenses are rated for 30W to 100W machines, which covers the 40W level as well as 30W. Do not read a winner from this alone: the tube generates the beam and the lens focuses it, and none of the listings state cutting results. For the next step up, see our 40W vs 50W CO2 laser comparison.
Optics: the two 20mm lenses
Both lenses are 20mm diameter PVD ZnSe with a 50.8mm focal length and a stated transmittance of ≥99.5%. The Cloudray names the model PVD ZnSe D20 F50.8 ET2 in a meniscus shape with a 2.6mm thickness; the CNCOLETECH states a 2.0 to 2.2mm thickness and a 0.02 kg weight. Both claim a double-sided solid coating that resists wiping, and the CNCOLETECH adds high-temperature resistance. Pick by the thickness and model detail your holder needs, since the optics are otherwise near twins. When the new lens arrives, see how to clean a laser engraver lens before fitting it.
The 40W tube: size and installation
The CR35 measures 720mm long with a 50mm outer diameter, 28.35 in by 1.97 in in the dimension line, and the listing says to confirm your machine has slightly more space than that. It arrives with the high-voltage end and low-voltage port preconnected, the high-voltage connector included and a metal head. The maker states a nano gold catalyst coating and a TEM00 beam mode with glass-metal sealing; triggering voltage is 13KV with 9KV working, and current runs 4mA triggering to 20mA max working. The listing notes CO2 tubes are consumables and long storage can attenuate power, so buy when you are ready to install; see how long CO2 laser tubes last for what affects service life.
Warranty and support
Only the tube states a term: Cloudray replaces the CR35 if issues arise within 4 months of receipt, excluding man-made damage, with the serial number and photo or video proof. Neither lens listing states a warranty term. The tube listing also says each tube is checked before shipping and packed for safe delivery.
Choose the Cloudray CR35 40W tube if
- Your machine takes a 720mm, 50mm-diameter 40W tube.
- You want a stated 4-month replacement policy.
- You are replacing like-for-like power, as the listing advises.
Choose a 20mm lens if
- Your CO2 machine runs 30W to 100W and takes a 20mm lens.
- You want a stated transmittance of ≥99.5% with a 50.8mm focal length.
- You want the Cloudray’s stated 2.6mm thickness or the CNCOLETECH’s stated 0.02 kg weight specifically.
For more CO2 machine options, see best CO2 laser cutter for home use.
CO2 laser tubes run at high voltage: the CR35 lists 13KV triggering and 9KV working. Disconnect power before handling the tube, ventilate the work area, and never laser PVC or vinyl. Handle lenses by the edges; both lens listings note a wiping-resistant coating.
Project Match
- Replacing a worn 40W tube: the Cloudray CR35, if your machine fits 720mm by 50mm.
- Refreshing focus optics on a 30W to 100W CO2 machine: either 20mm lens at 50.8mm focal length.
- Cutting or engraving thicker stock: no cut depths or work areas are stated, so neither side claims an advantage.
- Materials and work areas: not stated on any of the three listings.
FAQ: lasers and CNC
Can the 40W tube go in a 30W machine?
The listing calls it a replacement for the same power or the same length 40W tube, and asks you to confirm diameter and length. It does not state 30W-machine compatibility, so match your machine’s original tube.
Is the CR35 35W or 40W?
The title and bullets say 40W with a 45W maximum; the spec table says 35W rated and 45W max. We trust the title and bullets: 40W rated, 45W max.
Do the lenses fit a 40W machine?
Both are rated for 30W to 100W, which includes 40W. Check that your machine takes a 20mm diameter lens with a 50.8mm focal length.
How many lenses come in each listing?
One. Both listings state a single lens: 1 count, 1 pack.
What warranty does the tube have?
Cloudray states replacement within 4 months of receipt for issues, excluding man-made damage, with the serial number and photo or video proof. The lens listings state no warranty term.
Related: how to choose a laser engraver, best CO2 laser cutter for home use, CO2 laser cutters, dual tube vs single tube CO2 laser and all laser engravers.
