a second step extending above the bottom surface of {HEAD ~ said housing} and positioned adjacent to {TAIL ~ said passage} 
a second step extending above the bottom surface of { HEAD ~ said housing } and positioned adjacent to { TAIL ~ said passage }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL