volume of elastomeric material is required to fill and seal off the annular space between the body 12 and the casing 10 than would be necessary if the seal were simply axially compressed furthermore the stretching of the inner extremity of the seal material over sleeve 24 prevents buckling of the seal along its inner diameter and the leakage which could result therefrom the fluid pressure introduced into the cylinder formed by sleeve 32a to set the seal also urges the piston 48 50 of the anchor actuator assembly in a downward direction with respect to the casing 10 to set the slips 34 when the downward force becomes great enough the pins 42 and 56 will shear the upper expander 48 may then move downwardly with respect to the slips 34 the upper and radially inner surface of each slip 34 is upwardly and radially outwardly inclined the expander 48 has a correpondingly inclined conical surface engageable with the upper inclined surfaces of the slips 34 thus the downward movement of the expander 48 with respect to the slips 34 urges the upper halves of the slips radially outwardly by a wedging action the force on the piston 48 50 will also cause the piston 48 50 to move further downwardly toward the lower expander 40 carrying the slip cage 32 and slips 34 with it the lower inner surfaces of the slips 34 are inclined downwardly and radially outwardly and the lower expander 40 has a correspondingly inclined conical surface whereby the lower halves of the slips are urged radially outwardly as they move down over the expander 40 in actual practice the two sets of shear pins 42 and 56 shear virtually simultaneously and the various movements described above in connection with setting of the.