When {TAIL ~ the index divider} is lowered into {HEAD ~ place} it compresses all sandpaper sheets below it to keep the sandpaper sheets from curling 
When { TAIL ~ the index divider } is lowered into { HEAD ~ place } it compresses all sandpaper sheets below it to keep the sandpaper sheets from curling
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH