This is a Samyang-made lens that comes with a Sony E (NEX) mount. For those who like to use a filter, this lens has a filter diameter of 67 mm.
From Photospecialist
Samyang 100mm F2.8 Macro Sony E-mount
DigiBroadcast
Samyang 7708 100mm F2.8 ED UMC Macro Lens Sony E Mount