Epson Progression U12 - Manual (Page 32)

On a 3.5-inch diskette, the write-protect device is a small switch
on the back of the diskette in the lower right comer, shown
below. To write-protect a 3.5-inch diskette, slide the switch
toward the edge of the diskette until it clicks into position,
exposing a hole in the comer.
switch
To remove the write protection, slide the switch toward the
center of the diskette until it clicks into position and the hole is
covered.
or switch so they are
Using Your Computer 1-13