Out of box and repackaged by a large local contractor, labeled "Bortoluzzi-Salice-Dual Slider", which when googled brought up some spendy hardware from a company called Salice. Looks like it might be intended for cabinet doors, but seems quite substantial and might be used with actual doors, as well. You be the judge. I can't find a model number or paperwork to tell me the model, which is why it's pretty darn cheap compared to what I saw.