Through bore pancake slip ring Through bore slip rings (also known as «through hole slip ring») are slip rings with a hollow shaft in the center. This series is designed for being installed with a flange on a sleeve bracket and it is offering a free inner space for either connecting the rotor to a rotating shaft of the customer machine or for leading through pipes or cables not affected from rotation. The hollow shaft slip rings are available with inner diameters from 3mm up to 300mm SRH1254, SRH2578, SRH3899, SRH50120, SRH60130, SRH70155, SRH80180, SRH90190, SRH100200, SRH140270-4P10S, SRH250550-5P Capsule slip ring SRC012, Capsule Slip Ring SRC018, Capsule slip ring SRC022, capsule Slip ring SRC015, A3M Mercury slip ring, A3S Mercury slip ring, A4H Mercury slip ring, A6H Mercury slip ring, A8H Mercury slip ring