These were made in Holland and introduced in 1995. They are currently out of production but are usually a bargain when you can find one in good shape.
The Dual heads are still available from vendors as the HQ1917/2 or the HQ2/2 and you can usually find them on eBay and the Internet(but I’m not sure how long they will be available!) Mine are originals and still function great but I bought a replacement set for it before the supply dries up!
I had a cordless three head Norelco but was not thrilled about its performance at all. I have a tough beard and like a lot of other guys I thought an Electric Shaver was not for me. I found a Norelco 242 LC used at a thrift shop for$2.50 and really bought it for the pop up side burn trimmer which comes with this model. To my surprise the shaver did a good job on my tough stubble! Never cut me at all and the pop up trimmer worked well also!(It works best when you give yourself a good razor shave and use this every morning thereafter.)
I have no shaving pain with this model and that is a pure joy after 40 years of shaving, (no blood either!) I like this model so much that I have been hunting another in case this one goes out but so far no luck! The quality on these Holland made models seem far superior to what is available now days.