Docking station - eSATA port to drive connection

The question asked below addresses as following, hard disk docking station by 3rd-party vendor. Station take 2.5 and 3.5 inch drives, hdd and ssd. Towards the host it offers USB 3.0 and eSATA interfaces. Towards the housed drive it support SATA interface up to 6GB or SSD x 1.

The vendor specifies the eSATA port speed to 3GB. However, I guess between the eSATA port and the drive plugged in there is not translation nor an adapter unit necessary. eSATA port pings could connect 1:1 to SATA drive interface. My local retailer has confirmed this assumption. Where does the lowering of the interface speed from 6GB to 3GB come from?

Vast majority of docking stations with eSATA port and compatible with SATA III drives and availble in sale 

are specified to 3GB regarding the eSATA port speed.

* Can it be that depending on the station model and/or vendor there is some translation or adaption unit within the chain 

eSATA port to housed SATA III drive and a cut-down of interface speed results from this?

* Can it be that the eSATA port specification of 3GB in product description is not correct?

Hello,

Take a look at this link. Hope it helps

Installing a WD SATA, SAS, or PATA drive in an external USB/NAS enclosure or Personal Video Recorder