The Samsung 850 PRO was a solid-state drive in the 2.5" form factor, launched on July 1st, 2014, that is no longer in production. It was available in capacities ranging from 128 GB to 2 TB. This page reports specifications for the 128 GB variant. With the rest of the system, the Samsung 850 PRO interfaces using a SATA 6 Gbps connection. The SSD controller is the MEX (S4LN045X01) from Samsung, a DRAM cache chip is available. Samsung has installed 32-layer pMLC (TLC) NAND flash on the 850 PRO, the flash chips are made by Samsung. The 850 PRO is rated for sequential read speeds of up to 550 MB/s and 470 MB/s write; random IOPS reach up to 100K for reads and 90K for writes.
At its launch, the SSD was priced at 130 USD. The warranty length is set to 10 years, which is a very long warranty, better than most other drives on the market. Samsung guarantees an endurance rating of 150 TBW, a typical value for consumer SSDs.