in some implementations the annular chamber 700 has zero pressure or substantially zero pressure the third seal 680 is formed at a first end 710 of the annular chamber 700 and a fourth seal 720 is formed at a second end 730 of the annular chamber 700 the fourth seal 720 may be formed from one or more sealing members 740 similar to or different from the sealing members 650 670 and or 690 thus the third and fourth seals 680 and 720 are operable to isolate the annular chamber 700 the downhole tool 10 also includes a sealing assembly 750 flanked on opposite sides by a first slip assembly 760 and a second slip assembly 770 the sealing assembly 750 and first and second slip assemblies 760 and 770 are provided on the tubular mandrel 20 the first and second slip assemblies 760 770 are substantially the same as and operate similarly to the first and second slip assemblies 155 and 505 with the exception that in the shown implementation the first slip assembly 760 includes a locking ring system 780 rather than the slip ring 50 however according to other implementations a slip ring similar to slip ring 50 may be used in place of the locking.