Difference between MPU-6050ES and MPU-6050

Hello

Could somebody explain me, whats the difference between MPU-6050ES and MPU-6050?
ES version seems to me quite cheap. I want to also know, if it is same quality?

I saw this on SparkFun eshop, so I am wondering if it is OK.

UPDATE: It seems this cost is not unusual, since DigiKey is even cheaper.
Photo was probably made from Engineering Sample. I hope I'll get production version.

By the way, I love InvenSense sensors.

Thanks