2ml easy switch to 4.5ml capacity with the extra 4.5ml glass tube, Thread: 510.
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Updated:
Price history and price alert
It doesn’t make sense to generate price history chart, because there is one price record which is: $29.99.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).