the sealing surface if movement or flexing result in contact between the insert and the opposed sealing surface application_number US 20467094 A description the apparatus a is illustrated in fig1 in the embodiment illustrated an on off tool is shown which has a top sub 10 including a thread 12 at its upper end 14 top sub 10 has an internal thread 16 which facilitates the connection of j slot assembly 38 j slot assembly 38 holds the insert 20 against shoulder 22 on top sub 10 insert 20 has a pair of internal seals 24 and 26 and an external seal 28 seals 24 26 and 28 are preferably made of nitrile rubber however other resilient compounds such as aflas u00ae made by asahi glass company kalrez u00ae made by dupont inc etc can be used without departing from the spirit of the invention in the preferred embodiment seals 24 26 and 28 are bonded to insert 20 on three sides thereof however different arrangements of seals and different seal types can be used without departing from the spirit of the invention in the preferred embodiment seals 24 26 and 28 are made of hydrogenated nitrile baker polymer specification e801 for example seals 24 and 26 can be used as shown with an o ring seal located in a groove used to replace seal 28 alternatively instead of using two seals 24 and 26 only one seal or more than two seals can be used without departing from the spirit of the invention in fact it is within the purview of the invention to use a nonmetallic insert 20 in combination with a bonded seal on at least one of its faces top sub 10 has a bore 30 therethrough seal nipple 32 extends.