There are 3 methods of finding out.
1.) Contact the manufacturer and ask them if the SSD inside their branded enclosure has TRIM.
2.) Install Crystaldiskinfo and look at the S.M.A.R.T information reported from this SSD there is a line that will show if TRIM is a feature of the drive. It will also give you other helpful info on health of drive and how many hours its been used and how many times the drive has been booted as well as some SSD's have a write odometer that will tell you how many writes in TB the drive has performed. *** Only issue this software has with external drives is that there are some USB to SATA controllers that do not support fetching the S.M.A.R.T data from a drive and so a drive sometimes has to be mounted internally to a SATA port to fetch this information directly from SATA controller drive information request.
3.) Research the Drive that is inside the enclosure looking up its exact model number and look at its feature for TRIM. If no information on it on the internet, you might have to open enclosure and write down the drive information and research it, that is if its a brand name drive within another branded enclosure. If its a really cheap external SSD then it could be a cheap knock off SSD board inside a cheap case and unknown. With no labeling for identification present the only method would be to connect this drive internally to have a direct SATA connection and use Crystaldiskinfo to fetch the S.M.A.R.T data.
