This is a HDD/SDD caddy for HP Proliant DL380 G5, G6 and G7 2.5" drives. Might also suit other models I'm not aware of.
There's a side channel inside the right wing of the caddy suitable for a 1.2mm dia fishing line or similar, which will bring the LED light on the backplane to the front.
Very handy for visual monitoring of the hard disks, since the rest of the machine's front panel does not carry disk diagnostic LEDs.
Cleaning the print
Cut out the built-in circular brim on the back carefully.
You might need to ream the front and back light channels for the fishing line to come through.
Adding LED light transfer
You will need about 25cm of 1.2mm diameter fishing line or similar flexible material. Pass the line from back to front in the right wing, then cut flush to the front for each of the two channels. Both lines share an elliptical center orifice.
The fishing line might need some help with a small screwdriver to get through.
Chamfer head screws are required or else the heads might protrude and make sliding the tray in and out difficult.