This is a very compact 135mm DKL lens and is perfect if you love the vintage lenses but want clear modern glass.
The DKL mount was used by several German cameras, including the Bessamatic, Kodak Retina IIIs and Reflex SLRs. Adapters for modern systems are readily available.
The lens is in good condition with light wear and works perfecly. The glass is clean and scratch-free. The focus and aperture are smooth.