Thru-wall Return Fitting
 
Many brewers prefer to re-circulate and/or sparge with the kettle lids on.  The thru-wall return fitting option makes this process easy. This fitting is generally mounted at the top of the kettle just below the rim.
Thru-wall fittings mounted in HLT or Boil kettles will include a silicone tube that reaches the bottom  of the kettle to prevent splashing.
Thru-wall fittings mounted in the Mash Tun will include a cork float silicone sparging hose.