Older Bruner softeners ( Model B-790-4 ) used an Autotrol model 160 valve in late 1970s and early 80s. This model is like the 155 valve in size, but does not use an "air check" on the valve. In this regard, it is like the 168 model. The thing that made this valve "unique" is the side mount By Pass connection. The timer assembly is the 440 version, and this was and is ( newer 440i ) used on most Autotrol valves to this day. The time of day is set by the small pointer. The large arm will "trip" at 2:30 a.m to push the "skipper" wheel that has days of regeneration. For each pin pushed IN the unit will regenerate that night at 2:30 - 4:00 a.m. Most of the parts for the 440 timer, and some of the parts for the Valve are still available. Most of the trouble shooting and service hints for the Autotrol 155 would apply to this valve.