C3750e-universalk9-mz.150-2.se11.bin -

The file is a Cisco IOS software image for the Catalyst 3750-E series switches. It is a "Universal" image with the K9 (cryptographic) feature set, running version 15.0(2)SE11 . Technical Breakdown

Cisco IOS Release 15.0(2)SE11 for Catalyst 3750-E Series c3750e-universalk9-mz.150-2.se11.bin c3750e-universalk9-mz.150-2.se11.bin

if you are still using older 12.2(x) or 15.0(1) code. The 3750E has limited flash memory (32 MB). The universalk9 image is significantly larger (~16–18 MB) compared to older ipbase images. The file is a Cisco IOS software image

verify /md5 flash:c3750e-universalk9-mz.150-2.se11.bin c3750e-universalk9-mz.150-2.se11.bin