Hello Resaw,
The model numbers SSDPEDMW400G401 and SSDPEDMW400G4R5 are both for the Intel® SSD 750 Series 400GB, 1/2 Height PCIe 3.0.
The difference in the last two digits, 01 vs R5, is for the original packaging from factory. SSDPEDMW400G401 is a generic single pack and the SSDPEDMW400G4R5 is the reseller 5 pack. Retailers normally sell any of the two model numbers individually, but the SSD itself will have the same size and form factor.
Just to clarify, you can tell you are ordering the HHHL (add-in card) based on the model numbers. All the add-in card models of the 750 SSD will start with SSDPEDxxxxxxxx. The 2.5 inch models will start with SSDPE2xxxxxxxx.
