conventional manner either with or without landing rings an annular pack off 24 of conventional design seals the upper end of the hanger body 22 to the inner wall of the spool tree 4 the pack off 24 comprises a locking ring 26 engaged with a pair of circumferential grooves 28 in the inner wall of the spool tree 4 the locking ring 26 serves to retain the tubing hanger 20 in position with the hanger body 22 seated on the shoulder 8 of the spool tree 4 the locking ring 26 is a loose fit in the circumferential grooves 28 in the inner wall of the spool tree 4 allowing the tubing hanger 20 llimited movement longitudinally within the central bore 6 of the spool tree 4 the tubing hanger 20 has a longitudinal central bore 30 in which is fitted a wireline plug 32 of conventional design a lateral bore 34 extends through the hanger body 22 below the wireline plug 32 the lateral bore 34 opens at a first end into the central bore 30 of the tubing hanger 20 the second end of the lateral bore 34 is aligned with the radial bore 10 in the spool tree 4 upper and lower circumferential seals 36 and 38 extend between the hanger body 22 and the inner wall of the spool tree 4 above and below the lateral bore 34 respectively the upper portion 40 of the hanger body 22 as oriented within the spool tree 4 and shown in fig1 has a tapered surface 42 forming a seat on which may be landed further wellhead components and equipment an internal tree cap generally indicated as 50 is shown positioned above the tubing hanger 20.