Abstract: A probe inlet apparatus comprises an annular seal member and an inner seal device both mounted within an inlet housing having an inlet housing cavity extending therethrough. The inner seal device comprises a seat member connected to the inlet housing and a seal member ball adapted to seat against a seat member opening to form an inner seal. The seal member is responsive to a magnetic seal member positioning force produced by a suitable magnetic associated with the inlet housing to be held in the seated position so as to form the inner seal. An elongated probe may be inserted through the inlet housing cavity to first form an annular seal with the annular seal member and then to contact and displace the seal member against the magnetic positioning force from its seated position to an unseated position allowing the probe member to reach a desired probe depth.