Pawel,
That part number goes to the following part.
Model: 10G-SR transceriver
Part# 10G-SFP-SR 57-0000075-01 , 10GE SR 300m SFP+
Based on the above information it will work with a VDX 6740. in terms of transciever part list please follow the below link. If there is anything else that we can do please feel free to let us know, thanks!!
http://learn.extremenetworks.com/rs/extreme/images/Pluggable-Transceivers-DS.pdf
Regards,
Samantha Newman
Technical Support Engineer
Extreme Networks