Just a heads-up for folks that have this chassis with 3.5 hot swap trays. They come with plastic insert to mount the 2.5 drives in these bays. These also fit nicely with supermicro 3.5 hotswap trays as well. However, I see a design flaw. They completely block air flow and cause the drives to run hot especially SAS or high speed drives. I think can be addressed by sawing off some recess. I could see this being potential problem with the Dell adapters that were discussed here on the forums (9W8C4,Y004G) too. OTH, HP 661914-001 one seems to have nice recess for airflow. Thought this might help someone prevent thermal issues while sourcing these adapters.
Intel 3.5 tray with 2.5 adapter
Intel 3.5 tray with 2.5 adapter