I own both a Sinar F from the early '80s and Wisner 8x10 Technical Field from the late 80s. I have found a Sinar P in the local camera shop that has interesting markings. Most Sinar cameras are marked: "Sinar Swiss Made". This nearly mint Sinar P is marked: "Sinar International Rental System" on both the front and rear standards. I have never seen this before. Any idea about this and what years did Sinar mark their cameras as such? I do intend to buy this camera.