If you want something quite good for a reasonable price, this. No airflow in the room, check calibrate with the included weights, boom.
In my experience, a measuring tool you can't trust is worth than having no measuring tool at all.
Ok, I spoke too soon, just got word back from AWS. They have (2) Gemini-20s on the market ATM. The standard Gemini-20 is 20gx0.001g readability with an error margin of +/-0.005g. The upgraded model, GeminiPro-20 has the same 20gx0.001g readability but with an error margin of +/-0.003g like the other scales I mentioned above. The scale I and a lot of reviewers said SUCKS is the standard Gemini-20. I have not purchased & tested the gempro yet, but if you are absolutely mind set on going with AWS as your build, it's a no-brainer as to which of the two you should purchase. Still, I recommend dropping the $200+ on something actually worth money or as other dude said, just a get sub $50 scale with 0.01g readability as the build quality will be higher and the accuracy will be about the same even though the incremental readability is 10mg. Most of those cheap 1mg scales won't actually register increments properly under 5mg anyway if adding directly to a weigh tray. What you have to do is weigh your container, zero it out, take the container off & put it back on a few times to make sure it is staying zero'd & not walking, then with the container OFF the scale, add some powder, weigh it, REMOVE the container, add a little more powder, weigh it, etc. Don't try to add powder to your container while it is sitting on the weighing tray, it will not register properly & a lot of these scales auto-zero features will cause it to immediately go out of calibration. Always add MGs in small increments to the container you tared to zero while the container is OFF the weigh tray! Doing it properly you can fairly accurately add or remove 5-10mg of material & the scale will properly register the change. Good luck, but seriously if you are spending hundreds on chems & value safety & harm reduction then splurge for a decent anaylitical balance. If you have the budget, you absolutely can't go wrong with an Ohaus! They compete with Fisher Science, Mettler Toledo, & Sartorius (all $1500-$7000 pro lab balances) BUT also make consumer models that can be had easily on OldWillKnott or even Amazon for under $500. The Ohaus SPX123 is only $420 on Amazon ATM ($48 cheaper than oldwillknott's july sale price) & is NTEP Certified so you can write it off on your taxes as a necessary business expense lol. That is the cheapest I've ever seen them & I've been eyeing the Ohaus line of 1mg scales for quite a few years now. I shouldn't have spent the $250 on my My Weigh & just waited until I had enough for the Ohaus but live and learn! What I bought was effectively a Buick when if I would've been patient and waited I could've had a Cadillac for just a little more. 😐