laptop - concern about M2 SSD drive compatibility with my palptop

I have a Thinkpad P50 and I am planning to buy and install a M2 SSD drive on it.

The laptop has two built-in M2 SSD slot.

• M2 SSD slot #1: The laptop came with a M2 SSD with OS installed on it.


• M2 SSD slot #2: I am planning to buy and install a Samsung 850 EVO - 1TB - M.2 SATA III Internal SSD (MZ-N5E1T0BW) (http://a.co/6SJ5ZyY)

I have installed lots of IDE or SATA drives on laptops in past 20 years. SATA drives are quite easy to install and I have not had any compatibility issue with and SATA drive.

Also, I have been installing and using Samsung SSD SATA drives with no issue and they have been compatible with all PCs (or laptops) I had - even the older ones.

However, the This is my 1st experience with a M2 drive. The drive I am buying is relatively expensive and there is no return policy on it unless it is defective.

I wanted consult here and check if M2 drives are as versatile and compatible as SATA drives?

Is it possible that a laptop has a very specific M2 specification? This is the case for laptop memory. but I am not sure if M2 SSD are universal or not.

Update 1

Here is the lenovo part:

ThinkPad M.2 512GB SATA SSD (4XB0K48501)

Here is the part that I am thinking to buy:

http://www.samsung.com/us/computing/memory-storage/solid-state-drives/ssd-850-evo-m2-1tb-mz-n5e1t0bw/