SUB-CENTRALISERS™ J-tube Centralisers are engineered to centralise Umbilical, Riser and Flowline with j-tubes & j-tube bellmouths. By umbilical type (hydraulic umbilical, electro hydraulic umbilical, electro-fibre optical hydraulic umbilical and electro hydraulic and electro-fibre optical hydraulic umbilical with medium voltage cores) and by riser type (production riser, drilling riser, work over riser and others.