The BLX100 is encased in epoxy, to make it waterproof. The 10BL120 isn't waterproof, so when you take it out of the case, it's just a plain circuit board.
The only ones I do have (a whole 3) are all covered in liquid electrical tape and silicone, and, I only have those because they came with some cars and parts I picked up. All my old ones were lost in the fire.