An unique lens made by Dr. Weth, a retired engineer. Telestigmar lens consists of several parts used in various combinations to achieve diferrent focal lengths.
The main parts are:
1. Basic prime lens (250mm f/5 , 2 elements in 1 group) with aperture and focusing assembly.
2. Tube "N" with negative supplementary lens.
3. Tube "P" with positive supplementary lens.
4. Tube "Z" - spacer tube.
Tube combinations:
P + Basic Lens: 175mm f/3.5-22
N + P + Basic Lens: 225mm f/4.5-32
Z + Basic Lens: 250mm f/5-32
N + Z + Basic Lens: 315mm f/6.3-45

Close focusing extender tube and various mounts adapters were available from Dr. Weth
First lenses were made with M42 mount adapter, later also Exakta and Alpa.

You can read very interesting article about this lens here -
"The Magical Optic of Dr. Weth" by Peter Dechert.