I've had this for about 20 years; unused and stored out of the weather for the past five years or so. Used primarily for leaf shredding in the fall on a few properties by a professional landcare services provider. Stored out of the weather for the rest of the year. It's in good working order, with negligible rust. Shafts turn smoothly with no play.
This is made to run off the PTO shaft of a BCS walk-behind tractor, as illustrated in one of the photos. (Tractor not included in this sale.) This has the male half of the quick-connect attachment installed; makes changing implements easier. You'll want a tractor with at least an 8-hp engine, larger is better. I've been using it with the BCS 850 and a 12-hp engine. The unit weighs about 220 pounds.
A side chute accommodates branches up to about two inches in diameter, one branch at a time. Material to be shredded is added to the top hopper. Size of the processed material is regulated with either metal screens with different sized mesh openings, or metal bars that are installed across the exit port. I've only ever used the metal bars, as the screens tend to easily clog up, especially if the material is at all damp.
It has squared-edge, reversable, swinging flail bars currently installed. They are still usable, but they are probably due to be switched out for a new set. I believe a set of bars runs about $100. Sharpened cutters are also available as an alternative.
These are selling new for about $2,300. Asking $1,050. I also have a set of unused caster wheels that are larger than the ones currently installed i'll throw in for no extra cost.
Some more details and information can be found here on Earth Tools' website: https://www.earthtools.com/implements-chipping/chippershredders/