Confused about choosing the right shower handle

[kakers]

Currently I have the simple single handle knob for my shower. I purchased a Pfister shower handle but it doesn't fit. I need advise on what kind I should be looking for or if there is some kind of extension for the 16 tooth spindle thingy. My house is old so I am going for a cross handle or something plain. I can explain better in pictures......
(the images may be out of order)

what I have now looks something like this kind.....


Details:
-- The last pic (black fixture) is what I purchased and would like to use but it doesn't fit......

 

[Twowaxhack]

That’s a Symmons valve. Consult Symmons tech support with your pics

 

[kakers]

That’s a Symmons valve. Consult Symmons tech support with your pics

Oh- thanks.
I didn't know it was a valve issue.
But I guess I will look for what fits this brand. Thanks!!

OR.... does anyone know of a 16 tooth extension for a Symmons valve. I just want a new handle, I'm not looking to replace the valve.

 

[Twowaxhack]

Oh- thanks.
I didn't know it was a valve issue.
But I guess I will look for what fits this brand. Thanks!!

OR.... does anyone know of a 16 tooth extension for a Symmons valve. I just want a new handle, I'm not looking to replace the valve.

Symmons tech support will know what fits their valves. They’ll know every option.

 

[Geofd]

That's a model s-96-1,or 2 depending on if it's a tub/shower or just shower,there are a couple different handles that will work the stem model is ta-10 thats what the will ask for on the Web site or tech support, they are located in Braintree mass, they are bullet proof valves, home depot or Lowe's will have these parts

 

[kakers]

That's a model s-96-1,or 2 depending on if it's a tub/shower or just shower,there are a couple different handles that will work the stem model is ta-10 thats what the will ask for on the Web site or tech support, they are located in Braintree mass, they are bullet proof valves, home depot or Lowe's will have these parts

It's a tub/shower. On another note, I switched the diverter to be controlled by the spout. Do you think this is responsible for lowering my water pressure? note: I removed the bathtub spout completely so it is not the aerator (which I removed). The water pressure just started to be low when I started this project of replacing the handle and setting up for tiling.