Pentacon 135mm f2.8 Electric MC M42 thread mount with both front and rear caps.
The body, mount and glass are in nigh-perfect condition but there are two small issues.
1, The sliding hood is very loose, only a problem when tilted forward or back more than about 45 degrees!
2, The front element multi-coat has quite an abundant collection of marks, mainly around the centre, but amazingly they effect the IQ in no discernable way!
Otherwise this is a nice, stable and robust Pentacon lens with all the traits you would expect from that manufacturer.
£15 posted with the U.K.
£20 posted within the rest of Western Europe.
This is available to any location world-wide except for South America, Africa or the Baltic States as they have stupidly high customs charges and/or famously dodgy postal services!
Oh and not available to any land where there is currently civil unrest!