First, they're smaller than expected.
second, the tray is clearly plastic, sorry it bugs me.
I highly suggest the boxy-black eraser.
best eraser i've ever used, here's why:
-lasts a long time
-when erases, you can't tell if you wrote anything.
-compact, so it fits in your case
-black, so its different and unique
-super soft, and squishy, yet firm to hold.