GLC-T Vs SFP-GE-T Different points

May I know what is the differences between GLC-T and SFP-GE_T?

What I found out through net are as follows :

GLC-T

1000BASE-T SFP RJ45 100m transceiver

Specifications

Form Factor: SFP
Device Type: Transceiver module
Connectivity Technology: Wired
Wavelength: n/anm
Max Distance: 100m
Data Transfer Rate: 1Gbps
Fiber Type: n/a
Connector: RJ45
DDM: Without DDM
Operating Temperature: 0~70 °C
Application: 1000BASE-T
Compliant with MSA SFP Specification

SFP-GE-T

1000BASE-T SFP RJ45 100m optical transceiver

Specifications

Form Factor: SFP
Device Type: Transceiver module
Interface (Bus) Type: Plug-in module
Connectivity Technology: Wired
Application: 1000BASE-T
Data Transfer Rate: 1Gbps
Wavelength: n/anm
Max Distance: 100m
Fiber Type: n/a
Connector: RJ45
DDM: Without DDM
Operating Temperature: 0~70 °C

Each features are same , what difference be there. I have searched a lot of information ,but i have not found the answer.Who can help me with this problem?