13/16" Tube Insert ( 1041010 ) used to allow newer Valves with 1.05" distributor openings to use the older style 13/16" O.D. distributor tubes found in all older Autotrol 155 and some other older Valves.
Insert is placed into the bottom of the Valve opening.
An alternate method to solve this size mis-match is to replace the distributor tube with a new 1.05" pipe. This is accomplished by gluing a piece of 3/4" PVC pipe to the 1.05" bottom distributor ( MD1236 ) that we sell below.