Specifications:

Compatible Cisco P/N: GLC-T(10/100/1000)/ SFP-GE-T(10/100/1000) 1000BASE-T SFP transceiver module for Category 5e copper wire, RJ-45 connector
Form Factor: SFP
Data Rate: 10/100/1000M
Reach: 100m
Fiber Type: CAT5E
DDM/DOM: No
Temp. Range(℃): 0~70

How to decide if you need to buy a 10/100/1000base-t sfp module or a pure 1000base-t sfp module ?
1. Which one to choose depends on if the switch support SGMII interface or SERDES interface.
Case 1: When the switch supports SGMII interface, you need to choose 10/100/1000 multi rate sfp-t module.
Case 2: When the switch supports SERDES interface, you need to choose pure 1000Mbps sfp-t module.
Case 3: When the switch supports SGMII interface and SERDES interface, you can choose either 10/100/1000 multi rate or pure 1000Mbps sfp-t module.

2. Which one to choose also depends on what data rate the switch can support.
Case 1: When the switch supports 10M/100M, you can only choose 10/100/1000 multi rate sfp-t module.
Case 2: When the switch data rate supports 1000M, you can choose either 10/100/1000 multi rate or pure 1000Mbps sfp-t module.
Case 3: Some special switches can support data rate 10G or 40G, but can backwards compatible with 1000M data rate, you need to reset data rate to 1000M, otherwise it might not work because of dismatch.