Empty "L" Bracket Housing for 12 Day
Fleck 5600. Older PN 15494-01 ( 15494-03 is the same item, just with 2 holes for side mounting cover screws not normally required, but that is way they are all coming from manufacturer ).
If your Valve is the metered Econominder Version then use part number3415494-02
If your housing has broken, you can transfer the gears and timer motor to this new empty case. Not much fun, but do able.
For a quick and easy repair, order the complete 12 day "L" power head.
And if your Valve is over 20 years old, then a complete valve replacement
might be your best bet.