ring 262 of mandrel drive cap 260 lock ring 274 is received within an annular groove defined by upper inside surface 264 of mandrel drive cap 260 for securing mandrel compression drive 270 partially within mandrel drive cap 260 polished rod 280 is received within rotary mandrel 170 polished rod 280 communicates with mandrel compression drive 270 and the upper seal assembly 250 polished rod 280 additionally passes through the longitudinal interior space 188 of rotary mandrel 170 as shown in fig3 drive screw 290 is received within drive screw orifice 162 of wear sleeve 160 and within drive screw orifice 184 of rotary mandrel 170 for selective engagement with polished rod 280 in practice rotary seal unit 10 of the invention utilizes rotating mandrel 170 to isolate polish rod 280 from running elements such as upper lip seal 126 middle lip seal 128 and lower lip seal 130 by isolating polish rod 280 from lip seals 126 128 and 130 wear of polish rod 280 is eliminated tapered upper chamber 186 of mandrel 170 contains upper seal assembly 250 that seals and grips polish rod 280 so that polish rod 280 drives mandrel 170 multiple lip seals 126 128 and 130 form a seal therebetween space between multiple lip seals 126 128 and 130 communicates with exterior orifice 60 through orifice 88 in stationary cartridge 70 and spacer orifice 124 in upper lip seal spacer 120 an operator may open lower breather petcock 62 in orifice 60 to check for the presence of.