This uses peltier cooling and the stated cooling capacity is 50W. The effective wattage will be lower. If you search for “peltier” in this group you will find some good technical talk on using peltiers for cooling. I seem to recall that needed effective cooling capacity is going to be somewhere around 200 watts. Also depends on your starting ambient temperature and how much you are going to run your laser. So I got a feeling that this unit is probably going to be undersized to cool a 40W laser.
i believe some people may use a cw-3000 to cool their laser but having the right size reservoir is key. too small and it gets hot too fast. too big and it cant cool it fast enough. TBH sizing up to the cw-5000 is a better viable options it doesn’t use TEC-based cooling, or add frozen water bottles to mitigate the buildup… I use just a pump and frozen water bottles and seem to have no issue, but I also dont run my laser for massive amounts of time. longest run i have done is maybe 1.5hrs and it took maybe 3-4 frozen bottles.
There have been setups using peltiers that work but they usually involve 3-4 units linked together as a single unit is usually insufficient. as stated by others closer to 200 watts of cooling is about right, and only if you can cool the hot side efficiently enough.