An internal valve 7, further comprising {TAIL ~ a biasing element} to cause {HEAD ~ the equalization member} to move to the at least third operating position when the piston is at the second piston position 
An internal valve 7 , further comprising { TAIL ~ a biasing element } to cause { HEAD ~ the equalization member } to move to the at least third operating position when the piston is at the second piston position
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH